Oh yeah, now I remember! The truck has pivot ball front suspension......that's the main difference.
But I remember seeing lots of threads about how the best thing to do is just to buy the ST and if you want a buggy to just mod the body posts and stick a buggy body on it. The truggy seems to do better at the track.
There has been a long standing debate about whether C-Hub or PBS suspension is better for any car, ranging from 1/8 scale down to 1/18 scale. I can tell you that I've personally owned cars with both types, and if that's the only thing holding up your decision, it doesn't really make that much difference......you can make more of a difference with setup and practice.