well my modded Go 25 had almost as much bottom as my modded JPX 21...a little more mid for the GO, and the jammin has more RPM.... The Go was pretty awesome IMO, its midrange was killer, almost too much...The Go's are dam nice engines and seem to have better support... The JPX may have a little more pop under the hood, but not enough to worry about IMO, unless your like me and run on a black dirt track, then the Jammin's hard hitting bottom can be properly harnessed... for most track surfaces having too much hit int he bottom will hurt more then help...