My insurance company states that if I take it to there preferred shop that the repair would have a lifetime warranty

All Guarantees come from the shop doing the repair, not the insurance company. It doesn’t matter if that shop is under contract, on the preferred list or DRP with the insurance company! 

Bedford Nissan Collision Center stands behind our repair work.  We have the same warranty as the insurance company or their shop of choice.

We work with the insurance company, not for them. We may not be on their preferred list because we prefer to work for our customers first.