Wheels-Tires Switching To A Squared Setup, Need Help

16 GT PP

I want to switch to a squared setup for both Summer and Winter - I don't track this car and I live in the city in the Midwest. After the P Zeros wear out I'll switch to something more economical, but here's my plan until then and it should set me up to save money on tires in the long run. I just need to know, does it work?

Summer Setup
Front: 19x9.5 - Pirelli P275/40ZR19 P Zero - 5mm spacer
Back: 19x9.5 - Pirelli P275/40ZR19 P Zero - no spacer

Winter Setup
Front: 19x9 - BRIDGESTONE BLIZZAK LM-32 P245/40R19 98V XL - No spacer
Back: 19x9 - BRIDGESTONE BLIZZAK LM-32 P245/40R19 98V XL - No spacer

Is a 5mm spacer enough clearance? I've seen conflicting reports on multiple forums.

5mm spacers
http://www.ebay.com/itm/2-WHEEL-HUB...ash=item281ec107c8:g:hEgAAOSw6n5XumFX&vxp=mtr

7mm spacers
http://www.ebay.com/itm/2-WHEEL-HUB...ash=item281ec10812:g:vTMAAOSwZVlXumFf&vxp=mtr

10mm spacers
http://www.ebay.com/itm/2-WHEEL-HUB...ash=item281ec1082d:g:MGIAAOSwU-pXumFm&vxp=mtr

Regardless of spacer size, do I need new studs? I don't know anything about studs, so if I need them are there that are good out of the box?

Another forum member started talking about knurling and lost me'

Only one stud 6-10mm longer vs stock and will require dressing knurl on bench grinder.
Stock studs are 49.9mm with 0.625 knurl. cut n paste from phone notes:
610-435 57.94mm 0.628knurl
610-509 73.4mm 0.627knurl
610-437 76mm 0.628knurl
610-530 78mm 0.626knurl
610-333 90.5mm 0.625knurl

Click to expand...