Issues I had with the install were the headers themselves have raise the entire exhaust system by a cm or so, which lead it to foul on the heat shields. My installer I guess didnt property test the car post install..but I sure heard the racket. He extended the hanger (with a crow bar) to accommodate the raised system, and bend up some of the shields which has proven to overcome this issue.
Also a massive stumble from the install was reconnecting the O2 sensor plugs. 1 of the 4 pins was pushed out and was giving me an engine error. Please pay attention to this. Very minor yet annoying.
The sound of the front end has become very grunty yet wispy and induction like, I do really like it, almost sound like the E46 M3.
My system is;
Raptor Header
Stock Cats
Xforce centre + Y-pipe
Sti Mufflers.
I have zero drone, but a fantastic note when i rev it hard. Almost sounds like 4500rm, is the old 6000rpm. Which is fantastic. Was reluctant to rev past 4500 because of this.. not any more

The power has completely changed, feels rather endless across the entire rev range. Most impressive I guess is 100-140 in 6th gear. Obviously not sticking you to the chair but just pulls very well. All other gears have become weapons.
Thanks Tim and Matt (kiDo) for looking after your brands. Very impressive.