RE: Sig extra 300SX
For gas, they spec a 2.4 (40cc). I have the Extra and the Cap and love'em both. The Cap has a ST 2500 (perry carb) with a Mezjlik 18X8 (unlimited vertical) and the Extra has a ST 2000 (perry carb also) with an APC 16X8. I would not hesitate to buy either one again!