comPuTer, I have the type that fits over the original. These were very easy to install and I have had no problems with them.
Here are some links to both types, the first link is an install guide for the type that replaces the original. You may want to check that out to see what's involved in installing the replacement door spears as compared to just placing the other type over your present door spears.
http://www.ptdoityourself.net/ptcdspearguide.html
http://www.revelenterprises.com/pt_c...ome_spears.htm
http://search.ebay.com/search/search... door%20spears
http://www.jjproducts.net/PTCruiser/...ideSpears.html