Carfax is often 'incomplete' and they recently settled a class action law suit in the US b/c of it. It's only as good as the information reported to them (when they use it) but don't expect it to be overly accurate. My wife's car had an accident (minor - but $2500 in damages) where police were called and a report was written. When I went to sell it 2+ years leter, I disclosed to the buyer the accident. He didn't beleive me as it didn't show up on carfax - until I showed him the pics and receipts. Go figure.
Anyhow, w/ a '99, I think you are looking for p/n 986.331.161.03
You can check for yourself on the Pelican Parts PET catalog:
http://www.pelicanparts.com/PartsLookup/HTML/986_USA_KATALOG/501-01-Frame5.htm
It is something you could replace yourself, but it is a part of the rear suspension/cross members so you want to inspect for other damage and you will probably also need to have an alignment done afterwards.
Good luck and keep us posted.