so much misinformation in this thread

your m50 should spin up the two t25's no problem (i thought they were 28's, but regardless) but a twin setup on our six is a worthless complication. you would better off trading them for a single bigger turbo.

as far as what is safe, its up for debate. I have a few thousand miles on my holset powered m50tu @ 25psi. 10 psi is a nowhere near the power potential out of tiny turbos like that, I would say 4-500whp CAN be safe for a DD with proper charge cooling, tuning, and maintance without cracking open the engine for anything.