I had the same problem. Once I put in a full exhaust and a tune, my car feels very fast even when it's 100degrees outside.
The tune is what really made the difference IMO. Not sure how or why, but the car just pulls hard at 100 degrees, while at 65 degrees it pulls very hard. Whereas just stock, it pulls decent at 100 degrees, and at 65 degrees it pulls hard.
I'd recommend a full x-pipe (catless or HFC), and a tune from a reputable company.
Hope that helps.
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
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