i'm also torn between the 17" subzeros and the 16" slipstreams.
yes, the stockers are 16" rims, but they're also 16x6", and weigh in at about 18-19lbs (guesstimate). the slipstreams are a 16x7" wheels, +45 offset, and weigh 13.5lbs! so, you can run a 215/45/16 falken azenis (my plan

), get tons of grip and better acceleration.
but, on the other hand, the 17x7.5" subzeros look badass, and weigh 16.5lbs. still, 3lbs is a quite a lot considering how underpowered our cars are (P5).
rishie, your custom fitment from rota, is that an increased offset?(+50?)
if i get the slipstreams, it'll be gunmetal or bronze (i have a silver p5). if i get the subzeros, it'll be gold. wheee!
peter