I was wondering if I upgrade from standard 15" Alloy rims on 2013 PiP to Prius Plus 17" rims, is there a software (firmware) update to address rim size change or do I require a mechanical upgrade?
No. You put need to put on tires with a smaller diameter. so you replace the 195-65x15 with 205-50x17. This results in just about the same diameter.