[Braymond141]

This guide is intended to be a cost effective solution to mounting the OEM GT tray to your M3 bumper. In addition to the financial savings, you will also be able to increase the tray extension to 110mm (95mm stock) and the MM panel will continue to function as undercarriage protection. This is a fixed mount solution.

Stage I - Use this as an alternate method to Motion Motorsports crummy hardware.
Stage III - Use this to install the Abtrieb Satz (Tray Strut Kit) to your OEM mounted GT tray.

Components Needed and Rough Pricing (w/o shipping or taxes)
-OEM GT Tray PN: 51 11 2 267 457 ($322.45)
-Motion Motorsports Underpanel Kit ($160.99)
-MSportParts Tray Strut Kit ($199.00)
-MSportParts Tray Mounting Kit ($65.00)
-Replica Velocity Splitters ($40.00)



Tools Needed
-M8x1.25 and M12x1.75 Rivnut Tool (heavy duty required for M12 rivnuts)
-Drill and Drill Bits
-Dremel Tool and Cutoff Wheel
-Metal Chamfer Tool (on a drill press is recommended)

PLEASE NOTE: Your results may vary depending on the condition of your bumper cover. An OEM bumper cover in good condition is essential for a proper fit. Replica bumpers have not been tested.

STAGE I

Start by prepping your bumper for trimming. This part is not necessary but it helps keep the MM panel from sitting weird resulting in fender liners that are difficult to fit. Cut along the molded ridge. It's very easy to follow this ridge and get a nice clean cut.





Install your OEM lip spoiler if you haven't already. It must be fully secured and in good condition. Now is the time to replace any of the mounting hardware and the lip.



Motion Motorsport's panel does not fit properly within the factory bumper lip so you need to do minor trimming. Test fit your panel to determine how much to shave off. Marked here on the edge. GET IT RIGHT, NOW. The panel must fit squarely in place in relation to the bumper.



And shaved down. Fits snug now.





You'll want to prop the panel up and clamp it into the final position. It is critical you get your panel exactly where you want it and your holes drilled perfectly. If you wander with your holes on the second stage of drilling, your rivnuts may not line up! Rivnuts are not a mounting solution you get a second try at. You do have some wiggle room though.



Start drilling into the bumper cover using the 9 mounting holes already on the MM panel. This is step 1 of drilling. You have to remove the panel after the first round and make them bigger to fit the rivnuts next.



Remove the panel and using your new pilot holes, carefully drill them out to final size to fit the M8 aluminum rivnuts provided in the mounting kit.



Select the drill bit that allows the rivnut to TIGHTLY fit into the hole. Install your rivnut and use your tool to secure the hardware in place. These Aluminum rivnuts are designed to mount to thick plastic.





You will need to chamfer the bottom side of your panel to use the mounting kit M8 tapered screws. During this process you will elongate the original MM mounting holes to achieve the proper chamfer depth, this is OK. You want the supplied M8 screw to sit flush with the MM panel surface. Here you can see the panel attached to the bumper cover. Hopefully you did it right and all of the screws install straight into the rivnuts.

***Pics of chamfered holes coming***





STAGE II

Now you move on to the fussy bit; lining up and installing the mounting hardware for the OEM tray. Your fit and finish depends on your attention to detail. Measure 10 times, drill once. If you mess this up the tray will not sit right. Full OEM tray extension is 95mm from the tip of the stock bumper lip to the edge of the tray. Shown here I'm installing mine at 110mm. Pick anything you like between 95mm and 110mm.

For this process install your replica or OEM splitters. Make sure they are even and installed correctly. If done right, you will use them to help line up the panel where you want it.

***Please Note: You do not have to use my rivnut method for this next part. You can simply drill holes and use a bolt/nut combo. You will need the outer mounting bushings from the kit and I can sell them separate***

Start by placing your OEM tray on the now installed MM panel. You want to carefully measure everything over and over till you are happy.







Mark your holes and use a center punch to prep for drilling.





Here you can see I made minor adjustments after marking.



If your MM panel fit squarely on the bumper cover your holes should all look even with the edges.

Drill the middle tray mounting holes into the panel (through the bumper cover too to prepare for the next step) and install your M12 rivnut supplied in the kit. You will need a HEAVY DUTY rivnut tool to get these to compress.



You also need to drill the bumper cover to accept the rivnuts backside. Use the holes left behind from the panel prep. Remove the panel to do this and make them a little larger to make the panel install easier.



Here is the rivnut backside popping through the bumper cover.



Reinstall the MM panel
Mount your tray on the two center mounts you just completed. Check to make sure it all looks right before proceeding!

Now take the kit supplied outer mount bushings and slide them into position on the outer mounting holes between the tray and the MM panel.





Use the M12 bushings and a drill bit that fits snug through them to drill into the panel. This makes it easy to drill the outer holes without marking anything out.



Remove the tray again so you can drill out the MM panel to accept the M12 rivnuts.



Install your rivnuts, and remount your tray to the MM panel. You should have a nice solid setup. *You will have to open up the holes on the bumper cover to accept the rivnut backside just like the middle mounts.




STAGE III

***More images are coming***

Now you're ready to install this all onto the car. You'll want to install the MM panel frame rail brackets. [ Do not reuse your old ones and do not use the MM supplied body nuts. EDIT: I recommend drilling round holes in place of the square frame rail holes and using rivnuts. The plastic body nuts are not sufficient for long term, high speed use. These are supplied with the hardware kit .

Use a step bit to drill the hole out to match the M6 rivnut. Step bits work best in the square hole.





Install your rivnuts.



Drill out the MM brackets to fit the larger sized hardware. Don't do a shitty job like I did.



Bracket securely installed. Use blue loctite and don't over torque this.



Install your bumper ensuring you are properly aligning it left to right and all the way up on the bumper shocks. Do not install your bumper all droopy and half-assed. Get under the car and attach the MM panel to the frame rail brackets you installed. Use the MM supplied hardware to do this.

You'll be using the Abtrieb Satz (tray struts) mounting kit for this next phase. Yes you HAVE TO run these struts. The tray is too much for the MM panel to bear alone. This ties it all in for a super strong secure tray, especially extended out beyond the original 95mm.

***More tray strut mounting pictures are coming***

Mounting brackets installed


Drilling the M6 holes into the GT tray to connect the strut kit. I recommend installing the rods into the bumper mounts first and orientating them on the tray to mark where to drill. Measure to make sure each side is even and the center rod is straight before drilling! I provide basic instructions for the struts with every kit.



(You can see my bumper is a little droopy here, that was later fixed)



All completed

[Braymond141]

This is still a work in progress, but enough to get the idea.

[Nate047]

Good write up Brett, thanks for taking the time to share and for being so thorough. Sedan is looking goooood...

[Hasan Shaikh]

This is great. Thanks

[Sammyzuko]

Wow, this is awesome!!
My MM underpanel didn't line up properly within the OE lip so I really had to force it on and now my bumper is tweaked and the alignment is slightly off. I should've shaved it...might have to go back and do that.

[Braymond141]

Originally Posted by Sammyzuko

Wow, this is awesome!!
My MM underpanel didn't line up properly within the OE lip so I really had to force it on and now my bumper is tweaked and the alignment is slightly off. I should've shaved it...might have to go back and do that.

MM has had this issue since day one. I don't understand why they have not fixed it. They have revised their product at least once too. I thought about making my own competing panel, but local pricing in bulk would be more in cost than their sale price.

[M_Parallel]

Nice.

[Sammyzuko]

Originally Posted by Braymond141

MM has had this issue since day one. I don't understand why they have not fixed it. They have revised their product at least once too. I thought about making my own competing panel, but local pricing in bulk would be more in cost than their sale price.

I waited until a couple months ago to buy the MM panel so I thought all of the kinks would've been worked out by now. Over the years I've learned to wait for products to be on the market for awhile to work out issues and to see if the initial glowing reviews hold up. I figured the issue must be with my car as I had never heard about a fitment issue before. Surprised they haven't fixed it too.

[NolliM3]

Right on time, I just bought the Motion Motorsport panel...awesome presentation Brett; although, I am surprised to hear of fitment issue...have read here that it's the "go to" panel.

[Sammyzuko]

Originally Posted by NolliM3

Right on time, I just bought the Motion Motorsport panel...awesome presentation Brett; although, I am surprised to hear of fitment issue...have read here that it's the "go to" panel.

To be fair it's still a great under-panel, but there's just a bit too much material in the area Brett pointed out. It can easily be filed down now that you know what to look for.