no i dont have a vacuum pipe connected to it, apt just modified my fuel pressure, to keep the fuel there up to 20 psi, checked on their lambda on the road and its fine (done 9k now on new engine), no pinking, fuel isnt to bad, i get 210miles out of 34 quids worth of tescos super (which my car loves over optimax now)

went to santa pod there and back last weekend 260 mile round trip, done 3/4 of a tank cruising at 70 to 80 mph.

so the need for a 5th injector isnt always the only opition to fuel for lots of air input, as my car shows, but it depends on the tuner i suspose