Tacoma Towing Question

That's weird. They (Thule) don't even show that type of product available for the 2002 Tacoma. Just roof & hitch options.

That's an error in the category on Thule's web site.

The 421 is on my Tacoma, via the XK1 2005+ Tacoma adaptor.

The 422 is simply a taller version for F250's and the like.

Both are bed mount truck racks. I sell them.

Bed racks aren't usually spit out by the fit wizard. You have to click on "multi-purpose". In the paper catalog, they were always in a completely different section until this year.

Many "sports" Thule dealers, including the bike shop I work at, usually forget the Xsporter exists. It seems that most of them are sold by ladder rack dealers, truck outfitters, and some rare watersports places.

Do they work on just rails, if you don't have any sort of tie down things already mounted on them?

If you have an overhang, like 99% of the trucks in the world, they'll work fine. The XK1 "Tacoma Kit" is only required because the 2005+ Taco needs it.

The Xsporter normally clamps between the bed rail and the overhang, just as a cap would be clamped over the bed.

Call Thule direct if you have specific fit questions, they're quite good (as is Yakima) on the phone.