I have the G37s. I got it in 2008 when it came out. The parts wear out quickly and are very expensive. You will need to change the brake pads in the front and rear by 45000 km. ( this is the life expentancy of the brakes ). This will set you back approx. $800.00. The tires are bridgestone Potenza 050 and you will burn them out in approx., 50000 km. Spinelli Infiniti told me that these were the only tires you can get that are the same model front and rear for the 2 different sizes in the 19". they wanted $1950 installed taxes in. I checked around and you can get the Potenza 760 sport which is in the same category on the Bridgestone site ( Extreme Performance ) I got them for $1050 instaslled taxes in.The maintenance on average will be approx. $125.00 a month
Hope this helps