BTs do punch a lot harder than a small turbo when it does kick in though, and you get a good 3000-3500rpm worth of decent torque held to the limiter. Unlike the standard units that wither and die off too quickly.
I'm sure I was seeing around 0.5 bar boost on my Stg 1 ed30 at 2000rpm, just for reference, and then 1.7 spike by 3000rprm, and then it gradually starts fizzling out from there. Frustrating! I've gone for a TTE420 to get something in the middle of the two extremes.
I remember when I had a GT35R on my old VR6. It didn't do much until 3500rpm, even on that big old engine. sh*t head flow though. I got wasted by a Honda S2000 rolling into it at 70mph. I was in 5th. He must have been in 3rd or something
But it was a real world example of where being in the wrong gear and turbo lag means a car with half the power can walk away from you