AP $500, Cyborg $1450, MBRP hot pipe $110, DHM Race intercooler $900, custom tune $250. That adds up around $3200. On Cobb's web site, Fiesta Stage III is $2960. That is fairly close from Stage III to hybrid turbo. A true big turbo adds about $2,000 from DHM and cheaper with ATP but they use a modified stock exhaust manifold.
You can piece together a FMIC, downpipe, AP and call it "Stage III" but it's not the same. Also, the intakes seemingly do nothing.
I think "Stage III" is a poor value, stock is nice for warranty purposes, Stage 1 with an AP is nice, adding a better FMIC makes sense (Stage 2), after that step up to a hybrid, after that go DHM Quick Spool, after that go with a bigger turbo, aux fuel and an ethanol tune.
If you have the money and want big power, it makes sense to go straight from stock or Stage 1 to DHM Quick Spool or when you go Stage 2, get a FMIC that will support a big turbo or hybrid well. That way you don't wind up replacing parts more than once.