Craig (Nopsi) has a T25 on his A12 (1172cc) engine with a 2" SU in drawthrough configuration, and there is no real lag to speak of. It makes useful boost at 60kph in top gear up steep (and I'm talking steep) hills where you'd normally be going back to 3rd. And it drives like a factory built car - your grandma could hop in and drive it to the shops. Sure, she'd probably wonder what the whistling noise was... And it goes well too, and so far he's only running 7 or 8lb boost (about 0.5bar on his metric gauge).

I've done a bit of work on his car, and have had the opportunity to drive it quite a bit, and am pretty impressed with it. Especially as it is in early stages of tuning/development. Its also worth mentioning here that with the manifolds off, there is absolutely no evidence of "fuel pooling" anywhere in the plenum or other part of the inlet system.