I drove both on a track (Lexus had a track day for the IF) before I bought my M3. The Lexus sucked on the track, no feedback, trans was terrible, brakes were pretty good, engine was good. M3 was way faster and way more fun...
On the street I'm not sure which is better, but BMW's have a feeling about them that the Japanese cars don't have, even though they are typically built better...
Needless to say I bought a M3
///M3 e90 6 Spd Manual - Black- CarboTech RP2 Brake Pads - AFE Cold Air Intake - UUC/Corsa Axel Back - UUC Short Shift Kit- ESS FlashTune