You didnt mention if you had a boost gauge. If you dont you'll need that for when you are manually controlling boost.
Disabling the FCD is easier than raising the fuel cut, you would need to plug a vac hose, cant remember which at the moment. If you are on stock boost (9-11) you would gain approx 10 horses per pound.
With that, and a good downpipe, you could be running high 200's in RWHP. Not sure how much, too many variables, including the condition of your engine and ignition components.
Go to
www.mr2oc.com, click on the MKII MR2 section, then the 3S-GTE section, and read EVERY PAGE of the "Turbo Dont's" thread that I posted.