I actually have one on my race car. The guy I bought my car from put steeda sway bars and adjustable shocks on so the car would be drivable on the street. With Coilovers and skinnies its not too bad. Considering that my car is on skinnies it does pretty well.
this is actually for a buddy of mine.. hes more interested in the corners than he is the straights. he has sub frames, upper and lower control arms, and is considering a tubular k member, and when he replaced that, he was going to get that sway bar, but he nor i had heard anything about them as far as how much they help out. i appreciate the info tho!