[Alan L]

I am with Bill on the pick of the era for the cars. Of course there are other options, but it is hard to go wrong with that make and era. I spent ages going thru the same scenario before getting my SC. Still love it after 20+ yrs.
I am with PeteKz on his critique. It can be hard to walk away after setting your sights on something - but this one does have a bunch of red flags. Red flags on a 911 =$sss. Honestly, a really bad one, if someone gave it to you, you might be lucky to break even on getting it in good shape - with no account of your time. You want something that looks a bit more honest - since you are not the guy to do a complete teardown and suck up the unexpected.
I bought my 930 off the internet - runs like stink, freshly rebuilt engine, blah blah. That turned out to be a hastily replaced 2nd hand piston/cylinder, and it was 2 steps foward and one backwards, at least 2 engine outs, and a fistful of $s for the next 18 mths. Luckily I could do it all myself, but I nearly threw it in the parts bin at one point.
Alan
Edit. It is a bit like buying a house. Once you have looked at them until you are sick of it, when you find the right one, you will know it straight away, and be able to make a quick confident decision and sale - which is often a benefit in your favour. Because by then you know what you are doing, and looking for.