For sizing a turbo, you need to know your engine's volumeteric efficiency and have a shop do the math. For the most part, you'll want a turbo that spools quickly instead of flowing a large amount of air because that's one of the things that affects the driveability of a car the worst. Usually the larger turbos spool slowly leaving you waiting for the power to come on. Once they spool, it's hello traction problems.

Smaller exhaust housings that can be found in Mitsubishi 13c, 14b and 15g's are probably a lot more streetable on a 1.8L than a T3/T4. When you see "Stage 3" or "Stage 5" somewhere, just remember how you plan to drive your car. It sounds to me like you described a "Stage 1" kit by your driving habits, or intentions with this car. You don't want a T3/T4 or Garrett Ballistics series turbo on a daily driver.

A T3/T4 will sure let you put down a lot of power, but without upgrading your internals, you won't be able to reach that setup's potential. You'll wind up waiting for it to spool so you can NOT use what it's packin'. You're better off with something that has a smaller exhaust housing (If the car's not being built as an all-out drag queen). heh.

For 6-8 PSI, a 14b, 15g or Garrett T-25 are more than enough. A 13c will spool when you blip the gas from idle. A 14b can push 18 PSI and flow around 450cfm if it's ported properly. The 15g is a better midrange flow turbo. It's not good for higher pressures (abouve 14 PSI), but you really don't want anything near that for a OEM internaled Honda setup. The T-25 won't offer the high-end flow of the Mitsubishi turbos, but it will spool a lot faster. Like 500 RPMs faster, and flow nearly as much. The advantage of a quick spool is that the power comes on down low in the powerband, allowing you to use more of the RPM range with boost. Less laggy.

You won't find a 14b, or T-25 in a turbo kit. Those are "junkyard" turbos. The Greddy kit comes with a 15g and it's a good all-around performer for Hondas. Worthless on a Mitsubishi. What can I say? They're very different engines. What works for one doesn't always work for the other.