Well, I disagree with Chris about this "the last Superleggera was a waste of time, and not much better than the standard Gallardo" or however he worded it...
I have driven both back to back to back with a LP560 and LP640 a 18 or so months back, and the standard G is just... flat, and boring. The SL came alive, sounded better, had better throttle response, more low end torque, more high end pull.... then the LP560 had more low end pull than the SL did, but other then that, felt flat like the standard G. The 640 was just gobs and gobs of torque, and believe it or not, has a more compliant ride than any G has.