My stage 1 FG intercooler is the same as stage 2 kit except it doesnt come with intercooler piping. (core, no piping) The stage 2 kit is very capable at 400kw atws...we have seen 550kw atws but the outlet temps do start to rise. The stage 3 kit requires no metal cutting but there is a lot of cutting of the radiator support panel which is made from plastic...and is replaceable if you need to return to stock. If anybody wants a total non cutting kit I can cut the top 80mm from my stage 2 core ....and I guarantee it will still outperform the stepped PWR unit. (extruded intercooler cores are THE most in-efficient of any intercooler type on the market). I could also produce a stepped core but there is just no point...the "stepped" part of the intercooler that pokes up behind the plastic bridge between the headlights will measure approx. 460 x 80 x 30mm....that's a small amount of nothing as far as heat exchange goes. Kev