GT2540: IMO, this turbo is a big piece of shit. This is my opinion as I
haven't tried one. But, looking at the maps, it looks like a pile of shit.
I have heard anecdotal evidence from people I respect that it works pretty
well, but I wouldn't put one my car and find out. There is too big of a
size mismatch between the 53.8mm turbine and the 76mm compressor. Also, it
is insane to run a .64A/R on the turbine given the flow capacity of the
compressor. This turbine and this compressor are both really good on their
own, but they are worthless together. Total mismatch. Save your money.