New Jammin CRT setup?

Hey guys, I'm thinking of trying a new motor/battery setup in my CRT. Currently I'm running a Neu 1515/1y on 4s truerc 8Ah packs(on a V1 MMM). It is a great setup, it is defiantly enough for the track, but I think I want more power. Am I crazy? Maybe those who have seen my setup in person can chime in(Finnster, Arct1k, Mike) I know I have a high quality setup, maybe I just need to try some better lipos? I kinda want to try a 6s setup. How does a kb4510xl(1200kv) on 6s sound?

What about THIS lipo for my current setup? What about going 5s with my 1515/1y and gearing down?

Opinions?

Thanks!