Like I said I have seen all versions of the O.S. .18 running in front of me, and I have seen both the TRX 2.5 and TRX 3.3 run and there really is no difference in power between a O.S. .18 and a TRX 3.3 . Now if you get a O.S. .18 ported by a good modifier and try to compare that to a stock TRX 3.3 then yes there is no comparison.