"gives the turbo 12 more HP,"
You must be reading K&N literature. The pcm has parameters for how much air it takes in. It will only read so much. The K&N and other cone intakes suck hot engine air. For less than $100 my modified airbox with a custom turbo up pipe, no silencers, K&N drop in filter and 2" ram air sucks all cold air and breathes just as well, with the exception of no hot engine air. The K&N intake does look nice, though.
As for the extra almost 40 hp with the FIPK, exhaust and stage 1 it is a bit of a stretch. A flow through exhaust will help the turbo spool up a bit faster but but don't believe the hp claims from manufacturers. If you really want to get some serious extra hp then get a VAK ucp, AGP wastegate, and dual stage boost controller to go along with stage 1, better breathing and and a 2 1/2" catback flow through exhaust. Along with other mods my GT is scary.