You should definitely do the replacement if you really love the car and it never gives you issues. I have a Sunfire that I would be willing to slave all day every day to fix it if it ever came to that, because its a great car and rarely has issues (nail in tire, battery, adding coolant- simple things). Its a 2001, with about 140,000 miles on it and counting! I learned my lesson with putting it on the back burner when I stopped driving it for a while because I bought a 2007 Torrent. My newer, lower milage, twice as expensive Torrent ended up blowing a gasket 3 months after I got it and cost me more in damages then my Sunfire EVER did (and I've had my sunfire for 8 yrs vs my torrent for 1 yr). This just goes to show- its a 50/50. Even if you get rid of your old car, your new one may give you issues even worse. I'd just keep the old one and repair it since its been good to you so far =)