240sx with an sr20det swap is probably the single most popular drift car, next in line are the pre 93supras, and the older rx7's and the drifters love the old AE86 corollas...... you don't want too short of a wheelbase because a short wheelbase makes it tough to keep the back end from sliding completely around, however too long and it can be difficult to manuever and get the back end to stay out when you want it to. contrary to popular belief it doesnt take alot of horsepower to drift.
you can drift 2 ways for the most part with alot of varients
the more popular less power less money way is to slow down and as come into the turn, grab the hand brake to get the car sideways and at the same time pop the clutch and control your drift with the throttle
the other way is how your buddy in the GTO was doing it, when you literally have enough power you can just break them loose on a whim at any speed, basically you pop the clutch instead of pulling the handbrake... and carry it all the way thru the turn. hope that helped.
i may be wrong but ive heard the KA's are better than the SR's for drifting...