another thing, your speedometer will under read with bigger wheels....if speedo says you're going 100 for example, in reality you might be going 103-105 kmph so just a bit careful at traffic lights and speed cameras...try to find out if someone, maybe the nissan dealer, can re-calibrate the speedo for you; i've been wanting to get mine done but haven't so far...i went from 15-17 too but my speedo hasn't put me in trouble with the cameras yet...so i'm guessing a 2 inch increase hasn't affected the speedo THAT much..best of luck