I guess I should have been more clear. I'm not really worried about the turbo lag... It's more of a throttle response time than anything else. Regardless of which mode I'm in and I've tried all various options, off the line take off is always about 1 +/- second lag before the car actually takes off.
I also think this issue is specific to the 535 (not 550, 335, 135). I drove a 135 a few weeks back and did not notice this issue at all.