considering swapping wheels & tires with a fellow model S owner. car1: 2013 85. 19" Model S Base Wheel. car2: 2015 p85d. 21" Turbine Wheel - Grey The tire sizes are identical - his p85d is not staggered. All 8 wheels are 245/35-21. My question is: what, if any, obstacles do we face? Can we just switch wheels or do we need to add/remove/change anythong. i.e. TPMS? Other than the price we settle on (and changes to efficiency, road noise & handling) are there any other concerns we need to be aware of and address? Thanks in advance!