Custom piston for custom $$$? Or for the same price? Also I might be acuiring a T4 Garret ball berring turbo

Its HUGE! Its a cutom job or somethin, its got a tiny little turbine side and a huge ass compressor side! Someone told me it was a T66 but Im not sure till I get it! It could probably use a rebuild, how much would that cost? If I get it it will cost me $400... Is that resonable?