I've used extensions (w/antiwobble) for years on a wrangler with the 1Up Rack... two-bike. Super stable; no wobble; very stout. 1Up do offer a 4-bike option (with two 'add-on' racks) as well. I've used tons of racks over the years, and nothing touches 1Up. It uses a tiered stack to the rack...each bike sitting higher than the other. This does give you good clearance if doing mild off-roading. All that said, I have run a 4-bike set-up... and while stable, the overhang was far too much for my stomach to handle... It seemed to stretch for a mile. My ideal set-up was 2-bike 1up at hitch and two 1up trays on a roof rack.