I'm leasing and bought wheels/tires. I'm really liking the light, forged MORR wheels with Pilot Super Sports. I am keeping the stock wheels/tires to put back on at turn-in. I figure that I won't have to buy new tires then, so the cost is just shifted, and if I lease another 5, I can put the wheels on it.
The car really takes on a new character with the right wheels. I stayed with 19's for the performance/ride benefits, but 20's give you a nice look to stand out.
EDIT: Oh, I also got the BMW carbon filer spoiler. The car is AW, so this also stands out well. BMW gloss black grilles too. I am still mulling painted reflectors and side fender trim.
2015 SO/SO MT M3 :: Exec : Lighting : Adaptive : HK : CF trim : Full leather : DAP : Black 19's : sunshade
Crystalline tint 40%/70% on windshield : M performance mirrors, spoiler, splitters, lip : RKP diffuser : Fully dechromed
Bavsound Stage 1 : V1 Savvy hardwired : Self-coded, will code locally for beer or food