I still have to go with the E90 M3. I've had my E46 M3 for 3 years and ever since I sold it, I've been really missing it. And on top of that, I've driven my brother's modded S4 with around 400 hp...and I can't say that it was nearly as fun as my M3....so I would say go M3 all the way...Quattro just ain't all that fun.

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Lemans Blue X5 4.8is
Dynaudio
Diamond TDX 12" subs x 2
Xtant X604 x 2
Xtant X1001 x 1
VST 7" LCD x 2