I angled the setup to use the engine n pipe just as it came -no mods whatsoever.
The pipe is not at all peaky it is supposed to work well between 8000-10000 and it does .
After years of fixing so called packaged tuned pipes -this is the first one I have seen where it really works easily for anyone.
Tuned systems usually come with a "setup" chart of length to rpm header lengths and typically the new guy f--ks this up to a fare thee well.