Has anyone ourt there used the 66" exmark 35 hrs bs with the speed kit How did the fuel useage compare to EFI technology? What about quality of cut? We use 60 & 72" 28 efis with the mulching kits. The 28 efi doesn't have the guts in tall grass with the kit. The 60" does a fine job but we are wanting to increase productivity without adding additional personnel. My guys run the machines like its the Indy 500 so I'm concerned about quality of cut wirth the additional speed.