I think that the lag don't influence very much drifting, because gt4 don't simulate lag very well. Laggy turbos have very low torque at low rpm, however, very high performance na cars have the power and the torque close to the redline, but in mid rpm they don't have so much torque. The good of na cars its response to the throttle and the control that is caused by that, the turbo have more power and torque, but don't respond as well as na engines. It is like the d1 grand prix, that you have the na AE86 and the High powered turbo cars like S15, Rx7 and others.
The AE86 can keep up at the turn with the High turbo cars, and sometimes be FASTER, but there are systems to reduce lag.
In conclusion, Turbo or Na engine, have their advantages and disadvantages, and the way to drift with turbo is different from the NA, because in NA you may need to steep hard in the throttle to make the tires slide, but the power of the turbo make that easier, but then you will have to be careful with the throttle.
Personnaly I prefer NA engines to drift because I don't like to have tires spinning too much, making them harder to control them, and... What is better than a high revving engine?