I have it.
My advice is: if you will stay with K04, don't get it. It won't make a difference
If you go BT, get the Stage 1: same air volume as stage 2, but without the extra ports for meth and fuel. Using the extra injectors will require a lot of work and you risk ruining your car's reliability. And you will also have a CEL because it doesn't have flaps.
And for meth, use the "classic" solution, with BSH throttle pipe with slot for meth injector