yes to 2.5
of course you'll use HPTuners, but the tables in the stock tune only go up to 1 bar, so the tune doesn't read boost. if you use HPTuners off the bat you'll have to scale/fake a 2-bar tune using the supplied 2 bar sensor with the kit (which takes some very good knowledge of how the Ecotec tune handles things)
read on JBO to find out how people have handled higher boost/power levels than the default MP62 GM kit.. maybe talk to
Vic28, he seems to go pretty quick with his gear.