when they say minimal shaftplay there talking about the turbo shaft that connects the turbine wheel and the compressor wheel together, the shaft runs through a cartridge which lubricates it and keeps the wheels in balance and centered, if the turbo has lots of shaft play thats not a good thing because its most likely worn and needs to be rebuilt(which cost around 300 bucks, you can find turbo group buys for 450, i got my turbo brand new off a group buy for 470) or it has been knocked off balance by an obstrution in the cartridge and you have to send itoff to get microbalanced, every turbo has a minimal amount of shaftplay even when its brand new, its when it gets excessive that the turbo starts to become worthless.....if the turbine or compressor wheels are scraping the housing of the turbo, its not a good thing.....if something is sucked up through the intake or something blows in the motor and it gets spit out of the exhaust into the turbo, the wheels will become damaged and could possibly be suddenly stopped which would cause the wheels to be thrown out of balance and hell the shaft could break if it got bad enough, the wheels of the tubro should spin freely with out a lot of effort to move them, if when you turn the wheels it feels like junk is moing arouond or it feels like rocks and dirt in there, its once again, not a good thing........it should spin frely and smoothly without shaft play up and down or front to back....