it would take considerably more than any bolt-on turbo to get 500 hp out of the evo, trust me i just traded my 03 evo for my 05 X. your looking at an investment upwards of 12,000 - 15,000 to take the evo to 500+ hp. It's an awesome car, and capable of almost unlimited performace, but it is extremely expensive, as a reference the FQ 430 model (available only in the UK - FQ stands for F*&^%$# Quick) has 430 Hp and costs over $90,000. Moral here, you can do almost anything to any engine if you have the bank. Where there is a will, there is a way (to spend).