Originally Posted by xluben
For the 20G XTR I think that is mostly unnecessary. It's already running out of breath up top. Maybe some head porting would help, but raising the rev limiter on it's own won't really get you much, especially on meth (vs E85). I don't know that valves/springs would be worth it. I'd discuss this with a more experienced builder though.
No E85 for me or I'd still be on the VF
My thought with increasing the RPM isn't necessarily to increase power numbers substantially, but to make staying within the powerband without tickling the rev limiter easier. With your setup, for instance, you can drive between 4.5 and 7k and stay above 400whp. With 93 and meth, I don't expect to make those numbers, but think that the curve will be similar. I'd much rather be able to push until I feel the power drop and shift; knowing I'm still in the power band rather than potentially shorting it and dropping out of boost. Yes... more precise driving could fix this, but so could a little engineering.
That and I know that I'll want more turbo some day, no matter how much I tell myself that I'll be done with this
I'm a long way from buying parts, with the exception of an EJ257 short block that I have sitting in my garage in case I blow up something along the way. For now I'm just trying to feel out what is available before bugging shops about a build.
And, to stay on topic, I found you the perfect tint: