You don't need to balance if you got the wheel from kinugawa and if it's prebalanced (it has some shaved part on back of wheel)
The only thing you may need to do is machine the cartridge to fit the bigger wheel
Um, cough The chra is balanced as a complete unit, so putting a new piece on will change the balance of the rotating assembly as a whole. The new piece can be balanced perfectly but that does not mean it matches the balance
of the assembly that it's going to be fitted to. These parts, although being sold as an upgrade, still need to abide by the laws of physics and the entire chra should be re-balanced to guarantee the correct operation and longevity of
the turbo.
Sure, you might get away with it, but physics is physics irrespective of how much luck you dip it in.