I've heard of Tony Doukas. I heard he makes jet skis fly and builds custom parts for certain things. But that was a while ago. Go 4 mil ported stockers.
Done 100% correctly it could be awesome. Because I'm pretty sure my street bike is faster then my banshee, But at that point its not a banshee. You need to build a frame around the motor. And to do 140 on banshee front end is asking to die. There's SO MUCH that has to be changed to make it safe at those speeds.
I got that. I FUCKING LOVE IT!!! I have uni pods, vf2, 35 pwk t5, timing advance, shift star cut, trans cut. And a 4 mil, case matched porting, 20 cc domes. And my bike fucking rips. I'm more then content. With better tuning it'll be a rocket.