New Owner in TO of 2007 350Z Roadster

I had put this on another 350Z forum website (sorry…!). Then discovered your site. Did not get much of a reply to my questions. Thought maybe your site could help. Greatly appreciated.

This is a bit different of a car because it was a US car from the southern US, then sold to a Canadian Nissan dealership, Dealer converted US dash to Canadian dash, etc. Car was then registered with Nissan Canada and warranty (bumper to bumper 1.5 years left) is valid here. Car has approx. 17K kilometres and everything looks fine except tires were worn out. Mileage was verified by CarFax. Was somewhat concerned how tires were almost worn out already (original Bridgestones). So dealer and I made a deal that they would put on a new st of Bridgestones. Questions : (1) I would like to drive the vehicle from April/May to October with temperatures ranging from about 2 degrees celcius to 30. Would you stay with the original ones or order a different set ? (2) How long, under “normal” driving should one expect the factory tires to last.
(3) Is there an MP3 connector for the original non-Bose, non-sattelite radio - as the last owner removed the original radio and they are now installing the original radio back in. (4) due to the cost of the wheels/rims would you consider purchasing a warranty for $400-$500 which covers them for 4 years. (5) Any thoughts on extended warranty on this vehicle if only 1 driving season left on full Nissan warranty. (Last) Car looks immaculate inside and out except for someone changing the radio and tires just above wearbars. Underside of car looks clean, no dents, no rust, etc. CarFax was negative. Any other way of verifying mileage since odometer has been reported to be changed by Nissan dealership. Only thing I can think of - is to see if a dealership will check car servicing with the Vin number. Thanks for any replies.