just follow the direction and you'll do fine. if you need additional tuning info, check out www.teamassociated.com.
i believe they have setups for the T3 posted in .pdf format.
from my experience with the GT stealth tranny, all i can say is make sure all the gears are nice and clean. i remember rebuilding my tranny and felt a slight hesitation in one section of the rotation after the rebuild. i took it apart and after close inspection there was a very very tiny clump of lubrication that had small amount of junk in it. the gears are very precise the stealth tranny, so just make sure its clean and the gears will mesh flawlessly.