You have a few different options.... Go a complete external gate set up using the internal gated turbo ie... get a external gated manifold, tack internal gate shut, buy external gate, make pipe to fit external gate (eventually turbo will crap itself)
Or
Buy high mount manifold, buy slighly bigger turbo 3076 or 3071 with t3 flange, buy external gate, buy 4 bolt dump pipe, install.
For the first option it is a lot of (cutting corner) style work and a lot of mucking around with huge risks.
Or with the second option you can run a slightly safer set up running 10psi or more (if your injectors can handle it) have a bit more boost and its a matter of pull out and replace (less time mucking around)
If you want some quotes on prices for it pm me