2017 BRZ w/ PP - WRX Rims?
 

Has anyone tried to throw on last gen WRX rims to a performance package '17?

I believe they are 17 X 8 +53. I'm thinking I'll need spacers, how do I calculate what size spacer to get?

I previously owned a 2014 WRX with STI Brembos. That wheel required a 3mm spacer to clear the calipers.

Stock is 17X7, +48.

For 17x8 rims, +45 will be about the same putter width as Stock.

At +53, I think your tires will stick beyond the fenders a bit.

^^ Backwards... higher offset will mean the wheel is sucked into the fender further.