you got it man,get the HPD trail pipe wich i heard with time it always
end-up the bes setup for the 400,strong midrange and yes as you stated,
you can re-gear or fine tune the secondary to gain higher speed indeed.
i highly suggest hpd clutch components as well,or as the better fit for those quad.

 

so would i just be better off with an hpd trail pipe and a hpd agressive clutch kit? Which would be faster, that, or the rcr stage 1 kit?

 

i just checked hpd-inc.com and they pipe +silencer +clutch kit is out of my price range. I think im still going to go with the rcr kit, but im still contemplating getting the top end pipe. It says nothing matches is it shear accelaration, and i need top end the most over bottom-mid range. My question is though, will i loose any performance in the bottom-mid range with the top end pipe?