F82 BMW M4 Polyeurethane Lip Mounting Help

Hi all,

I currently have a 2016 F82 BMW M4 and I'd like to mount this polyeurethane lip.

Right now here are my current aero mods:

1. GTS shaped Carbon Fiber Rear Wing. It is mounted higher than the stock M4 GTS Factory Rear Wing. The mount isn't a great mount so it moves laterally at higher speeds. There is a mounting solution available (so the wing stays rigid) but it's around 600 USD so I'd like to see if I can come up with a custom solution but that's something I'll be working on later.

2. Carbon fiber GTS-style hood

3. F82 M4 GT4-style Carbon Fiber Canards

4. Side Skirts (These side skirts look like a straight line and are not curved or sticking up in any way)

5. Carbon Fiber Diffuser (Likely cosmetic and does very little)

My previous lip: (I bought the car with this original carbon fiber lip). This lip broke.

Some observations: Before when the car had the original carbon fiber lip, it had more oversteery tendencies (I prefer a slightly oversteery car) with the stock competition package wheel/tire setup (285/30/20 in the rear + 265/30/20 in the front Michelin PS4S) + stock suspension/alignment. When the lip broke, the car was noticeably understeery (probably due to the aero balance being upset). I have switched to a square setup now (275/35/18 all round Federal 595 RS PRO ... a cheap 200TW tire). The car is still a little understeery though less so now.

My thought process behind going with this lip:

1. It is cheap, looks good, and carbon breaks

2. It is aggressive, but not too aggressive. Ideally, I would go for a GT4 style front lip but those are expensive and I feel that it would upset the aero balance of the car. My guess is that the GTS shaped wing is mounted a little higher (level with the roofline of the car) so it would produce slightly more downforce than the factory GTS wing. Therefore, a GT4 lip/splitter would be overkill. I think the factory GTS lip (and replicas) are not that aesthetically pleasing and very expensive.

Why I think this new Polyeurethane Lip produces a small amount of downforce: I bought this lip and mounted it (with the screws which came in the box). I was driving at around 105 mph (170 kmph) and the lip simply got pulled underneath the car. I think the shape looks like it creates downforce and it seemed to get pulled aggressively underneath the car so I guess that is a signal that it may have been creating downforce. I would guess that if it was producing lift, it wouldn't get pulled aggressively downward, and may actually fly off over the windshield of the car.

My question: How should I mount this lip. I am thinking about using 2 or 3 screws (with nuts) on the left side and 2 or 3 screws (with nuts) on the right side of the lip in addition to the screws that come from the box. I'll also use doublesided tape but I suspect that will do very little to secure the lip. Do you guys think this is a legitimate way to mount it/have some tips? I do plan on driving this car at high speeds (250kmph) and I would hate for the lip to fall off.

Best option is to run the factory CS or GTS lip Or a good rep that has the mounting points for the oem BMW mounting brackets installed and then also use rivnuts installed into the bumper to greatly increase its strength.

Also filling the lip with expanding foam will greatly increase its strength. They sell 2 part mixable expanding foams meant for boats in varying densities that are very well suited to this use.