Looking at buying my first 350Z. Looks really clean and taken care of, however it has about 115K on it. 2003 with 6speed manual. Anything these cars are known for? Should I walk away? Any advice...

Early cars had a few issues most of which should have been handled by now. Carfax? it's nice to know the ownership history, I passed on a low miles multi owner car that had been repo'd at one point for a higher miles single owner. I'd look for a good honest car, something with no accident history not a lot of owners, no repo history. You might find a deal on a car that has some needs and can save some cash if you can do the work yourself, labor bills add up quick. In my case the car needed a couple of wheel bearings, tires and a diff bushing, this adds up to a lot of money if you are hiring out the work.

The ad says all service performed at a single dealer, one owner car. Clean carfax. Its priced at $8400 obo. I feel that's a bit high for the mileage. However, it is the track model.

That's actually a pretty good price for a low miles early track model, especially one that clean and well maintained. Just be sure it is a track model, with the correct wheels and brakes, you can check the vin to verify as well. seems many unscrupulous dealers advertise lesser models as track models constantly.