The turbine housing should have the .ar number on it. The .ar # along with the turbine wheel size is going to help us understand exactly what you have and help you down the right path. The fact of the matter is the fmw362 has a smaller turbine than the 66 so if you drop to the 362fmw, you're going to see quicker spool, obviously but as mentioned, you will lose out on the top. Those BW turbos have a plethora of options for the turbine so there are a ton of variables when determining exactly what may be best for you. If you're running 205/100's and you're having a hard time spooling that, have you tried data logging and have your tunes adjusted? Reallistically those injectors should spool that turbo with ease. Just my $0.02