It works decently to get you in the ballpark but I found it a bit clunky to work with. I found the Garrett calculator a bit easier to work with, and I just looked in the Borg Warner catalog for the comparable turbine and compressor. Granted my goals are much higher than the typical off the shelf turbo. I also did all the calculations to determine where my engine would land on a compressor map...Then I called Chris at CRT, told him what my goals were and he put me down for a turbo I didn't see in The BW catalog or on Match-Bot haha! If you're shooting for less than 900hp then I think it works decently to give you an idea of turbine size and compressor size. But usually it's just easier to call a reputable turbo shop and get a recommendation.