if it is running 305set up, the std t25 should be good for that spec, shouldn't be burning out turbo's the rate your are think you should get someone to look at it for you may simpley just need setting up.
you might want to check the oil lines to the turbo make sure there's no sworf in the lines causing it to fail.
which oil are you running in it ?
when your are running the car take it you let it warm up and and warm down properly etc not telling you how to suck eggs

might also be worth getting a uprated t25 or a t34 turbo with 360dec and stronger shaft
also a turbo cooler from airtec might also help make the turbo last a bit longer

might also be worth giving stu and msd a shout !!