I'm mounting new tires in on my 2002 soon. I'm looking for some colored valve stem and came across some 90 degree stem. I need some education in this area. How do stems work? and what are the sizes our car uses? or are they rim specific?

I really like these but not sure if it's usable :

http://cgi.ebay.com/ebaymotors/90-Degree-A...#ht_3026wt_1165