With the factory roof rack you would need either the 450R Rapid crossroad foot pack or the Thule 450 Crossroad foot pack.
As the load bars slide through the 450/450R mount/foot kit on the factory rack it is up to you as to what length load bar you want to use.
(The 450R uses an aerodynamic load bar; the standard 450 uses a rectangular load bar.)
Here are a couple of links to both versions*.
http://www.rackattack.com/product-pages ... ssroad.asphttp://www.rackattack.com/product-pages ... tem_type=2Chances are that the Thule roof "Rack" you are getting will not fit unless it came from another vehicle that was equipped with factory "Roof rack" rails*)
I've been using Thule since 1983 on all of my vehicles and they work very well.
BTW, I've sold this stuff for 20 plus years!
On our KJ I use three pairs of 450 Crossroad foot packs and six foot long 78" (6.5 feet) long.
Then I permanently mounted a pair of 400 "feet" with a 5 foot long load bar directly to the roof as a light bar.
(Search KJ Country for photo's if you are interested)
On top of the three load bars I have an "Old School" cargo basket and 11 cubic foot ski box mounted.
(We also have a 7 foot long M.O.A.B. {Standard basket with two extensions.} basket sitting in the garage that I need to install when my body is up to it.)
Thule has never let me down in the last 27 years!