The issue is tuners don't like tuning the fg xr6ts with stock turbos with the 4 inch full systems they say they need a bit of back pressure to control it. I'd love to buy a 4 inch dump and high flow cat and get it tuned but they think it will be hard to control boost so the venom cat and dump should help this? It wouldn't flow as well as a 4 inch so easier to control boost for the tuner I'm assuming?iv been told this from 3 big name tuners in Sydney so just wanted to see if anyone has had the same issue thanks