compass question,

https://g35driver.com/forums/g35-coupe-v35-2003-07/148631-compass-problems.html

 

While its possible for the large magnets on subs to throw off a compass i seriously doubt that is your problem, i am not sure of the location of the sensor in our G's but even so this is not likely your proble. As much as it sucks i would take it to your dealership, it probably needs to be calibrated or replaced. I work as a valet on the weekends and i have driven many different cars including a few G's that were not my own and could always see the compass working just fine while going around in the parking deck.