I'm going to be buying some patch panels soon for my 68 Cutlass S and I was wondering which company sells the best for quality and fitment. I need them for the lower fenders and passenger door and rocker.

 

The only "patch panels" that fit correctly are the ones you cut from used OEM sheet metal. The new production patches are all Chinesium and all fit like crap. Expect them to require a lot of work to fit properly.