i need some help deciding wich engine i should get for my jammin fte. buggy. i am looking at the o.s 21 v-spec , and also the jammin .21 , Axe Rossi Mamba .21, or the Novarossi N21B 2001 BF .21 ?? wich one would be best? the track ill probably be running on is medium-tight with a strait. is there any good info about the jammin .21??? please let me know, i need one soon! thanks