Hi

I am new here and hope I can get some advice. My wife's GA has rust under the doors and right behind the back doors, more so on the drivers side. I am considering replacing the rockers and any metal in these areas myself. Its a 4 door we bought new in 1999 and runs solid, just this rust.

1. is it worth fixing? Car has almost 200K miles on it, burns oil, but otherwise runs like clock work.
2. I found the rocker panels online, but no rear quarter panels, is this even available or do they need to be cut out of a donor car?
3. what other parts may be needed to get rid of this rust?

Thanks very much in advance for any information.