The 4 door sedan and 2 door coupes use a different lip. sedan - E39 M5 lip, coupe - E46 M3 lip
The difference is in the width of the trunk. I bought mine from the dealer, so got an OEM E46 M3 lip and got it painted professionally. I looked for a while and decided that I still do not trust ebay(maybe if the lips were universal for both cars), I was figuring on spending $100 on a lip and did not want cheap crap(nothing against bekkers). The paint is probably going to be more expensive than the lip by they way too. When all if said and done a lip is getting close to a regular M3 spoiler so decide which you like better and get that. Bavauto.com has lips too. The dealer charged $112 and I got 2 quotes for paint $180 and $130. I was getting other paint done so ended up not having to pay for paint at all, but that is a different story.
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