Hello and welcome!
Rust isn't a huge problem on the 370z yet, we don't sell anywhere near as many rust replacement parts as we do for the 350z.
If you want to disable Active Sound Enhancement (and you cannot do it programmatically with Nissan CONSULT) you can unplug (or cut) the ‘engine speed signal’ from the Bose Amp.
Other than that, just the regular maintenance stuff, they're fairly solid cars apart from some common faults like the CSC's but that's not something you're going to spot on viewing one unless the pedal feels sticky or won't come back up.
Worth checking if it's had the oil gallery gaskets done at all, if not, we'd recommend doing them at some point for peace of mind.
Also, the steering locks can incur issues but it's not as common as the two issues above.