I have a 2005 G35 6-Speed Coupe
Will be making some changes, getting rid of the Magnaflow Exhaust and I am looking for suggestions.
The car is dropped about 3" and I was wondering if anyone has suggestions/experience with performance headers & exhaust systems that aren't scraping all day/night long in a slightly lowered 2005 G35 Coupe?

Most of the exhaust is tucked up high enough into the unibody that it won't scrape, the lowest hanging parts are the cats and the exit tips. You can have any local muffler shop modify the hangers to make the exhaust sit higher. Also bevel the exhaust tips so they match the contour of the rear fascia instead of protruding down past it.

The cats are a bit more of a challenge since they're securely bolted to the headers, most test pipes sit up a bit higher, and again, it's something that a local muffler shop can modify but usually you have to pay them cash under the table because they're technically not allowed to modify the system from the cats upstream. If you have test pipes it's usually not as big of an issue.

Just shop around various local shops IN PERSON, and make sure to tell them you're paying cash, don't be an ******* if they say no, be charismatic