I ran at a track last year with my legend. Their track rules were the spec pack with spec motor or spec pack with 13.5 novak geared the same. They were identical on the track for a 5 min race. I ran all spec, and the same caliber of driver had the 13.5 in his with the 22t pinion and they were the same speed and punch. I would like to try 1 cell with 13.5 and the spec gearing.some of us have gone to 1s 4000mh 25c lipo packs at rosewood this year. we are still running the spec motors, cant seem to get them to go the brushless route yet. the 4 cell guys are running 20t pinion, 1s is running 35t pinion. we are still playing w/ the min. weights, but are at 33 oz for 1s, and 39oz. for 4 cell now. they seem to run close overall. the 1s seems to pull hard up front, but falls off more at the end than the 4cell. some of us have talked about it, and we all seem to agree that the new havoc 1s system w/ either the 17.5 or 21.5 will probably be the most economical ($149). plus this is a fixed esc, no programming like many of the others, which would be more in the spirit of the class.