to the N54. That is just insane. I thought I was blessed to be able to get a gain of 50whp with just $700 in modifications (K&N Drop-In Filter, 3" TBE, & Tune) on the 4G63, but 90whp with JUST a tune!? That is unbelievable.
I would think you'd be over the 400whp mark with downpipes, a cat-back, and intake. Its amazing what direct injection, an extra litre of displacement, and one extra turbo can do...