A newbie here looking through craigslist to purchase a used z. Pardon me for not going thru the thousands of posts. Could anyone answer the following questions? I know there's a lot of "it depends" regarding these.

Is there a particular 350z/370z year or model that one should prefer or avoid?
Many Zs have been modded. Are there any mods to avoid because they can be very difficult to install or say "this guy drives his vehicle hard?" I am particularly wary of electrical problems.
How many miles is a Z engine and tranny good for? What would be the "breakeven" point where one would say "I wouldn't purchase that car because it has 140K miles on it?

Thanks very much for ya'll's experienced opinion.

Also, are there any other sources (other than this board) to look for a used Z?

We really need to get a 350Z buyer's guide up here, especially since they're so inexpensive to buy anymore. Anyway...

The '03 & '04 models are known to have problems with the power window motors eventually failing. Also notchy shifting in the 2-3 & 3-4 shifts. If the previous owner had a transmission replaced with the later CD009 transmission this will not be an issue.

The '05 track & 35th Anniversary (6MT*) models had oil consumption issues. They had the RevUp version of the VQ35DE engine and some of those engines had a bad cylinder hone that was the source of the oil consumption. I've got a 35th Anniversary and had no oil consumption until the the mileage was really high.

In 2006 all 6MT models came with the RevUp engine.

In 2007-08 the 350Z got a newer twin intake engine, the VQ35HR along with a bit nicer interior than the older 350s. My suggestion is that if at all possible purchase from these model years only. You'll get a better, stronger engine and a better interior.

Welcome to NICO!

*Six speed manual transmission

The 07-08 went to the hydraulic throwout bearing which is much more expensive to replace and apparently they had a pretty short life span. My suggestion is to look for a stock unmolested car, better have one that shows a few bumps and bruises than one that someone did a hackjob repair on. I'd avoid salvage title cars. the condition is far more important than the milage. When I bought my 160k mile one owner 06 I chose it over a similar car with half the miles but had intake, shifter, and a hackjob stereo instal, it also had a repo history and several owners. I still feel I made the right call. Set your budget then get the nicest car you can afford, the repair bills can get costly especially if you have to hire out the work.