i have a 6 speed manual fg xr6 with genie headers high flow cat and a 2 and half inch system , growler intake and a custom made intake pipe. car has been thrashed since 20.000kms and now have 102.000kms. havent dyno ran it yet or tuned it but still beat my mates bf xr6 manual with full tune with 194rwkw can any body tell me how much power u gain from a custom tune ?

You'll gain 9000rwkw. Honestly, it depends on how good the tuner is. If he's s**t, you won't get sweet f**k all. If he knows what he's doing, you can maybe expect 10-15rwkw and a bucket load of torque.