I used to rebuilt myself many turbos with oversize bronze bearings because i'm in machine shop work and you can't do nothing when the shaft piston groove has been enlarged (worn-out). The only thing I do worried is when Chinese do copied, are they they using same quality material for turbo shaft, pistion ring (which retain oil from going into exhaust manifold) and bronze bearings...the rest doesn't really matter except roughness od internal casting for air flow speed....I will ask questions to sellers as well as Z1 to deal a something but I talk to an Arizona speed shop from where comes the Sylvia S14 turbos that I have bought for $1500.00 in 2004. But the japanese who suggested me to by them (BB trubos capable of 300HP and 22 psi) tols me they were bolt-on...of course but just on the manifold so I had to made all mods 2 years in advance of Z1 GT600R turbos to use them....and my 8 engine rebuilt have scrapped the turbo bearings with .007" lateral play now...running a JDM engine with good compression....i'm ready to boost more on stock engine...and yes not sure I can assemble GT600R turbos without engine removal...Z1 as the answer because I would like to selle them my S14 turbos as core and get $850.00 if they offer $325.00 for each BB cartidge adding both exhaust and compression housings...and buy their GT600R ready to install...and $400.00 more compared with buying 2 cartidges and 2 actuators only and assemble my turbos myself...or buy chinese for $700.00...and preach they will resist for 4 years minimum
