I own a 2006 g35 coupe and I wanted to upgrade the brake system to Brembo. Any ideas if the 03 and 04 fits in the car? How much would they run used?

 

check the marketplace on this site.

 

The 03-04 Brembos should bolt right up to your car. You'll need the rear caliper bolts specifically for the rear calipers as well as lines. Used I've seen them go for around $1500 on average. Check my350z.com as well in their classifieds.