They are the stock turbo on 2nd gen DSM's, yes. Turbos can be rebuilt and still perform well I think, just 1) know what you're doing. 2) buy a quality rebuild parts/kit 3) get it done professionally.

the T-25 is good up till about ~13-15 psi, around there its about as effective as a hairdryer. You can T-25's from thunderbirds, Merker's, and something else... forget what it is.

The late 80's Nissan 300z comes with a single T-3, while the newer 90's Z32 has two T-22's.

The t25 isn't a real efficent turbo but it does build boost quickly due to its small size