I have bought a car off Craigslist. Just don;t give them your cash until there is a bill of sale and a title in hand. I saw the asking price and I was like $5 is just way too much. I offered 4.50 and was beaten at 4.51. I was a little furious, but now that I know its a fellow clutchfan I can live with it.
I don't know about offerup. I sold my car on craigslist, and it was at the time 1 of a kind car. Clean title, low miles and impeccable. I didn't try CarMax, or other known websites to try to sell it. I just put it on with my mind, if it sells, yesssss. If it doesn't sell, yessss. I didn't let any of the buyers drive it because I'm the only owner and had it for 10+ years. I showed to 2 buyers, the 1st buyer wanted, but money was low. The 2nd buyer came and bought the car with cash. Don't be skeptical of craigslist, you may find gems. S2000- I have driven it. It is adult-go kart. Every bump and broken road, you will feel it. It is not a practical car, only for weekends. I love driving the car at night, you can see the headlights go up and down. OP- Avoid car