Assuming that your car is the silver one in your signature, I would skip it. Metallic silver paint is almost impossible to match. I had a nightmare experience with my last car, a metallic silver (much like your M3) 350Z. It was painted three times using top-of-the-line paint (PPG), the first time by the shop, then by the auto paint supply store, and finally by a PPG rep. It didn't matter. I saw the same thing on every silver 350Z with a body kit where only the bumpers and skirts were painted.
I'll be SHOCKED if your car comes back without a noticeable mismatch.
2008 IB E92 M3| BBS | KW | Arkym | Platte Forme A.G. | Active Autowerke | K&N | Fabspeed | Dinan | Evolve-R