I’ve been considering adding long tube headers to my 2011 GT and would like some input. I know the old saying applies, you get what you pay for, but after looking at websites, is there a big difference between brands the Pypes $1200 set up vs kooks $1800 set up( or any of the other brands in between)? Are there any issues with fitment, leaks? My main go is sound if it makes more HP, then bonus. Any advice would be great.