275/35/19 is much better. I'd only recommend going with a 30 series sidewall if you're tire width is 295+. I'm at 285/30/19 in the rear, and I have some regrets. I'll be going 275/35/19 on my next set.
2009 E92 M3 | Alpine White | Black Extended | Advan RS | Turner Test Pipes | Dinan Axle-Back | OETuning | Eibach Springs | UUC SSK | VRS Front Lip | VRS Type I Diffuser | Matte Black | RPi Scoops | MS Filter | Yokohama AD08 | F1 Pinnacle
Special Thanks: Gintani | OETuning | eAs