Glad to hear you have a good mechanic.
I would find out what was done as a first step that will say what can or can not be done to help improve what may or may not have already been done.
A built SVT would be a higher HP stock motor. But if the motor just got all rebuilt then I dont see a very good reason to tare it out. the time and $ to go from ZX3 to a SVT motor may cost more $$ and take more time.
Honestly, working on cars is nothing but time and money... it sounds like your situation does not allow you either right now. I would get a tune after doing some bolt on's. Do a full SVT 3" exhaust w/ header that's CARB still right? intake, possibly pull the head, and deck the head and put in a stage 1 set of CAMS and call it good.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)