I like reliability in my setups. Kinda like to keeap them around for a bit, I get mid 30's on 14 and 9xl, not really interested in top speed except on the 150ft straight on the track. I rather clear the jumps with short acceleration and be consistant on track
MacII, for 4S i would recommend something like a 9XL. It will do great. I run a 10XL on 14 cells and its to much for a track even as large as mine is. 4S will be very nice on a 9XL.