...or any NA engine.

Question is, what are the critical factors that influence why the EJ255(?), in other words, the RS/TS engine, wasn't more popular to be turbo'd?

I believe I only know of one company that provides product for that engine, Ludespeed, but why?

Is it due to compression ratio? I'll look it up, but I'm pretty certain that the RS engine is higher.

It really threw me for a loop when I rode with a friend in his RS-T and saw that he was only blowing like 3 psi and creating some pretty impressive power, but I never asked why he was unable to push WRX comparitive boost. I just figured it was due to hardware.

The block is the same, save for the 'non vs. semi-closed deck'.

The difference between thepistons and rods are a very good reason, I know, but if you're building up your engine, it's a no brainer that you'd be upgrading those pieces to forged, anyhow.

I'll have to research bore and stroke differences while I'm at it.

 

I apologize. I guess I still don't know where to post. Alex or whoever, move as you see fit.

 

I guess it boils down to compression ratio is higher and materials are softer. It would seem as though the manifold from any EJ should be compatible.