the aem ems isn't out at the moment for the DBW cars (ie STi) although that would be the ideal engine management to run if you can find a capable tuner. as far as manifolds full-race is still working on a 40r setup and it will be a while till they're done, i'm assuming you want 600+ on race gas? Even so, you may want bigger injectors, not sure if your gonna run out or not. A tilton carbon-carbon clutch would be the way to go but if not I would run a standard carbon tripple disc like an exedy, spec, etc. Honestly you may be pushing your 16k cap trying to do this, at 600awhp you need to start looking at your axels, and built sti transmissions are far from cheap, at the very least 5k+. As far as fuel pump, you may want to run an external with custom lines at that point, right now I myself am trying to figure out exactly what I'm doing for my 40r setup. Your perrin fmic may actually be big enough, those cores are pretty large, your just going to need to do custom I/C piping. Flipping the manifold will make the car a bit more responsive although there is some skepticism about that, if you don't care to keep the a/c I would see no reason not to, there's just a decent amount of work involved in doing that.