its a turbonetics 60-1 t3/t4(S housing) with a weird t4 turbine housing. Its got a t3 exhaust wheel but the turbine housing has a t4 inlet flange. I think its a stage 5 t3 exhaust wheel because its smaller than a p-trim t4 wheel but, bigger than a stage 3 t3 wheel. So you'd be able to use a .48 or .63 t3 turbine housing. Its in perfect working order, no shaft play. It's worth around $500. I'd be willing to trade it and $150 for the gt4088.