For off roading, the U bolt flip is intended to help keep the bottom of the U bolts from getting snagged and all bunged up. 4PlusProducts | FJ40 | Suspension Parts | U-Bolt Flip Kit - http://4plusproducts.com/fj40uboltflipkits.html.
Without any hesitation, I strongly recommend that you call the folks at Cruiser Outfitters. Describe your setup and intended use and they will advise you on the best selection.