Well, just as an update, I did a temp fix last night coupling the new pipework to the old stuff, and went out for a blast, now before above 6k revs the rev climb would start to slow down noticably, but now..... wooosh, its up there asskin for more and more revs, what a bloody difference, now Ive just got to work out how Im going to get the old lower pipework out and put the new stuff back in, it was a bit much for me late last night.
Now, theres an interesting question, what diameter pipework did you get with your viper? as I think im running 75mm but I think chris172 has some small stuff, maybe 60mm - I tell you what, the install must be a hell of a lot easier with 60mm than 75mm, cos its just crammed behind the light in my install, couldnt shift it!