A powerful but horrible engine "built" by Mitsubishi. To end the fued between the 3sgte and the 4g63, The 3sgte did come before the 4g63, which mitsubishi replicated in power but not reliability. 3rd gen 3sgte created 255hp on 7psi and the 4g63 creates 300hp on 18psi. A very unreliable motor that will probably blow before you pay that EVO off.
For your own safety, please do not mod the 4g63 or you can kiss it goodbye. Your best bet is to leave it stock and enjoy.