engine swap to a dci 100 engine (stronger internals , 26mm gugin pins on the pistons as appose to 25mm on the 65-80 dci's )
hybrid turbo setup, better manifold with straight through exhaust.
uprated clutch will help ALLOT.
as injectors go, you'll max out at 130 bhp down to the injector cycles is maxed out.
noones found a suitable replacement yet as the injector holes are smalled than average diesel's