Car buying advise?

So I currently have a 2005 Monte Carlo 3.4 with 160,000 miles. I just happened to have been looking online and found a 2007 Impala SS with 100,000 miles for $6,500. I decided to go and test drive it just to see if I liked it or not. Well I did enjoy the way it drove and it definitely has more power than the ol Monte, but then I told them the price was more than I wanted to spend. They came back with $4,800. There are some cosmetic things like "hot riding" damage to the hood. Looks like sun damage/clear coat peeling not sure what hot riding is. And a couple scratches. Are these cars decent and reliable? I know the LS engine is pretty good, but sounds like these have Tranny problems? Should I just keep the Monte, it is paid off but could pry sell for $2,500. Just looking for some car advise, thanks in advance! via /r/cars http://ift.tt/2u0u0Aa