ok guys so I got mine...and well...it didn't fit. I DO NOT BLAME the seller. As I have a custom bumper that was for my 335 to look like the M3. And I think this is where the problem lay
I'm really bummed about it, but I'm glad I didn't spend $1800 on one. So needless to say I'm will be selling this diffuser. I'm going to try and test fit it on a local guys M3 and see if there is a difference. If it fits his and he doesn't want it...then it'll be for sale