well... there`s headers and headers for sure, but even tti`s can have their fitment issues... my friend had to beat up his $$$ tti to clear the steeringbox. Once in you`re fine ( apart from extra heat in an already crazy hot enginebay) but trouble starts when stuff breaks and wrenching is needed. Cant get the starter out ( many boil to death because of the headers) , can`t get the steeringbox out etc etc. Every time you need to repair something , drain coolant , pita to get in and out
Sounds great, better performance, looks great ( when ceramic coated ) but I will never have headers in again. just my opinion though...