Hio Scotty,
welcome to the forum:thumb:
This earlier post on here will give you some idea. It's about an Auto but the rest is relevant.
http://www.peugeotforums.com/forums/508-76/secondhand-508-few-observations-263610/
As for the manual bare in mind these cars have a dual mass flywheel and can disintegrate at around 100k. These are a lot of money to replace.
I have a couple of 2l 508s in my fleet which I would recommend for what you need it for. I find them very reliable and comfortable for passengers. Larger than the 407 & much better in every way.
You need to keep the oil changed regularly with the correct oil & quality filter. I do it every 10k then service every 20k as per manufacturers spec.
Some early base models don't have the built in Bluetooth so watch for that.
Timing belt needs to be changed at 120k. They have a chain so not imperative but that's what I do.
Be aware the Peugeot has a Particulate filter in the exhaust system and will need a regen. if you do loads of short trips this may be a slight problem. You'll need to take it for a run down a strait road for 20 minutes once in a while.
Pretty good on tires. I buy good brands and I get good miles out of them.
Brake ware is OK. The rears seem to ware out quicker than I would expect.
I've had seven 508s since they came out and overall I've been satisfied with them. I've had 2 Gts, by far a superior 508. Just brilliant to drive. I did have some Passat's for a while. Bloody nightmare they turned out to be!
Grumpy.