Im just curious as to what makes you think that you need a rebuild now, or in your near future? And why going with an ej257 makes a "better street machine" than a ej205/207? You are looking at ECU issues that will need to be overcome right off the bat there that will add to your total budget. Another thing that would help is describing, or letting us know what you mean by "high" 300+ hp? I mean is that 399 AWHP, or are we talking 335 as thats 35 HP over 300? In no means am I trying to be a d!ck, just trying to make sure I or anyone else understands and gets the full picture of what you yourself are trying to build/achieve.
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX