I've driven all three housings.

Out of the three obviously the .48 spooled up quickest. That was on my old cossie running 350bhp (car was on greys)..was a really nice punchy set up for a road car.

My mate has the .55 on his (siemens blacks) and that too is a really nice punchy set up, slightly more lag but pulls harder when on boost.

My car is runing the .63 (again siemens blacks) and it is really quite laggy...HOWEVER it pulls like a train when it comes on boost!..only problem is it doesnt make it's full 2.2bar until over 4.5k rpm

I'd say the best comprimise between the three is the .55 with siemens blacks. My mates car is running 360bhp on that set up..cant remember exactly but I think he's running 1.7bar

Hope this helps