Wet kit with the nozzle ~ 4-6 inches from the TB. You have a fuel system capable of 300+, but it is still returnless, correct? The stang guys might get away with it, but the Focus ECU is a different beast. Trust me, I played around with N2o for awhile on my car and the fuel system gets "quirky" at high RPM when spraying.
The wet kit is the safest way to go along with a GOOD TUNE.
150whp/135lbs-tq @ 13lbs.