The S3 is VERY tunable out of the box, especially when I hear the new kits have the original rigid chassis, and the new flat chassis. Most of the upgrades I have are just aluminum versions of the plastic pieces. Alot of the stock steel parts can be replaced with lightweight aluminum. As for a main, if you can tune it to hook up on the track and be able to drive a-main level, then i am confident it will get you there. the only upgrade that is a big improvement is shocktowers, giving alot of adjustments, the rest is not 100% needed. if the track is smooth, use the rigid chassis, if rough and bumpy, use the flat chassis.