Yea well you never know what happens on the day of the tune, besides who knows exactly how much kw cars push most dynos give you a higher figure than what your car really has.
For example, I tuned my car with my safc @ chasers, i only had full exhaust system, fmic, bleedvale @ 12psi (that didn't even hold boost properly), pod filter and thats about it, the dyno sheet said 214.9rwkw, now thats hard to belive....
Every cars differnt but i'm just saying if i dont get upto 240kw on that much boost i dont really care anyway, i'm not after a power figure i just want everything to work the way its set up to... And with the turbo i've got and the setup i've got i just want everything to complement everything else. I just want to be on the safe side really, but seems like 550s will be the safest choice ey...