Gaz coilovers are decent, just choose the right springs often springs are so short to get the lows but not enough coil to allow comfort.
Poly bushes are a given, tighter arb also.
As for brakes, you can fit focus rs 4 pots, or for cheap alfa gtv or fiat coupe ones, justneed to knock up an adaptor.
Seeing you are going mtx, perfect time to canter the engine forwards as the blacktops were intended. Will give more room for turbo down low and pull top of engine towards fire wall better.
Loads of wasted space under inlet otherwise, see crazycages mk3 fiesta for how it can look.