Whether I'm driving my Z or my brother is, and he's driving his stock Z or I'm driving his, my car always pulls ahead of his. Granted, it's not a huge change and my car certainly isn't "smoking" his, but it's still pulling ahead. An extra 30-40 hp in a 3200 pound car isn't going to do a whole lot.
On that note, mine "feels" much quicker, probably because of the quicker, crisper throttle response, smoother power delivery, and stronger top end pull to redline.
Of course, things will change if and when I throw a supercharger on mine.
