Yeah, on second thought, maybe 1/2 offset is better for my track, it's very challenging, with jumps, six pack, or rumble strip on every section of the track.
I actually remember my other tires that are zero offset, they are RD Logic porcupine's, and they bite so hard in the corners on grass. But they weren't are good on gravel/dirt as badlands.
I guess I will just go for these:
http://www3.towerhobbies.com/cgi-bin...?&I=LXUVU6&P=7