I'm looking into installing an MPI twin turbo set-up with hopes of around 700rwhp. I want to know if i will be fine with a sc stage 4 or if i need to save for a complete rebuilt trans from ats or sc. Thanks.

Quite a few MPI twin trucks running the Suncoast stage 4.

SC IV here with no issues. I dynoed Friday with 691hp with 1149tq. Just make sure you have a good builder to put it together.