The thule products are excellent - you do need proper roof bars, not the factory jeep rails. Some of the cheaper ones that are similar i'd be wary of. I'd go the 951 myself, all their products can be keyed alike to, make sure if you do order more down the track you request that.
Cheap option is one of these...
Bolted to one rail and a short section of channel to sit the rear wheel in another plus some tie downs... worth the effort?
Saris racks are pretty good.
Pacific towbar ones with the velcro strap rather than the top plate if your on a budget.