[ZX3TUNING]

i'd also say stay away from the procharger kits. no tuning, requires moding to make it fit propperly and i'm still wondering about the use of the bottom mount intercooler...?

VF/FS kit:
best bang for your buck, easy to upgrade, great tech-support what more could you want

Powerworks kits:
expensive at first but worth it once you drive it. great power, unbelieveable drivability, easy to upgrade or retune for more power.

toms's stuff is not the end all be all of performance for the focus.
tom does good work, his parts and workmanship on those parts is top notch but his best tuning work is inhouse, not mailorder.