Depending on how much you want to spend, you might be able to get above 170whp (on a dynojet) with Intake, Header, 3" Exhaust, Stage 2 cam, 2.3 Head Swap with Port/Polish, and an intake manifold (Cosworth with modification, Weapon R with modification, or Top Speed Duratec I/M <--best choice) Don't use weapon R junk.
How many foci people use that brand? Let alone Mazda people. Add a set of SS 1 piece valves to your 23 head.
You could also do a DIY turbo kit like I am. You could put together a non-intercooled 6-8 psi setup for less than $2,000.
Otherwise, FSWerks Stage 1 is the way to go. Check em out at fswerks.com. Give Randy a call and tell him what your goals are and he will hook you up fosho.
The final option, is to go n/a built. 11.6-12.0:1 compression pistons, hard cam, aftermarket I/M, header and 3" exhaust. That will give you right around 200whp. A 23 get you 40-60 more hp & more grunt.
No you don't need to do a 23, more motor is always better
As for what felix said. You most definitely do not need to swap to a 2.3.<<
W/ that your leaving some power on the table. I am going to be putting down above 300whp on my stock internals 2.0. The 20 more than gets the job done.<< You never have enough, who are you kidding, come on. You do not need tubular control arms to help put any power down. And the Torsen diff is no longer made so that is out of the question.>> Look around & you can find them. The stock open diff will be completely fine with your power levels as long as you're not doing a million drags. Having a 23 to begin w/ gets you more grunt & a better flowing head. CFM's tubular arms gets the power down= lowers your 60' times &they are stronger & lighter.
If you do decide to keep it N/A, then you will want to have 2 mufflers on your exhaust to help keep quiet with the header. Example, FSWerks Stealth exhaust. But FSWerks will not sell a 3" version of their exhausts, so that will be needed through Trubendz.
If you are going boost, then FSWerks 2.5" Race Exhaust will be perfect.[/QUOTE]