RE: tuning the mt2 18ss
The .18ss is an absolutely horrible engine. Mine lasted one gallon and it has horrible compression from the start. Sell the engine right away and get a .12/.15/.18 cvr.
The .18ss kit is good because you get some good bits with it. The upgraded drivetrain is NEEDED for any powerplant, the RTR is useless. Shim your diffs.