I just recently got a 2008 G37 with 49,000 miles and when I looked underneath it I saw that there was some pretty decent rust on the exhaust system. Just wanted an opinion on if this is too much rust and if I should consider doing something about this. Also what can be done about this other than getting a whole new exhaust system. I'd appreciate any feedback, thanks.

 

Welcome to the site, and yeah, looks pretty bad. Not much can be done there, if it was the body rusting that might still be covered but not the exhaust. A new axleback setup would be the plan unless you want to go full cat-back. Axlebacks such as Top Speed & Beluga look nice and cost $300 or less, a quality catback would start around $1k.
I assume you live in a place w/ harsh winter, or at least the car came from such a place.
Pretty common in the rust belt.

 

I mean does it look like it seriously needs to be replaced ASAP?

 

Looks quite similar to my 2012 sedan, or any car that's more than 2ish years old here. Winter isn't friendly to cars.

 

Not until it starts leaking, and on a vehicle that's not lowered you may be ok for a long time (since you won't be scraping it on a regular basis).

 

I wouldn't replace it unless seeing it just bothers you or its leaking, like blnewt said. Mine was similar while upgrading the axle-back and I had to grind and drill the bolts out. My car was from Texas originally so I don't really know how it happened but, if its just your exhaust, then you're in the clear, easy fix.

 

As others have said, it's not an emergency. But for a couple hundred bucks you'll have a shiny new axle back and a much improved exhaust note. If you were thinking of doing any mods now's just as good a time as any.

 

Its looks ok to me and as long as there isn't any leaks its fine.