You basically want the cake and enjoy it's flavor ? , I'm thinking a t-3 turbine mated to a high flow 60 or 70 trim compressor would be a nice trade off for the spool time. unless you want ball bearings which only changes it marginally. I'm using a holset hx-35 and am impressed by it's response , i have also tried the hx-30 with some very nice success. but those were both on a 16v motor.