I recently loaded a cab with a Celestion G12M-65 Creamback to be used with the Mercury V I have arriving in the very near future. I've been breaking it in with the Impala and it really sounds great. I've had this speaker paired with some other amps in the past, and didn't really like them, but I'm definitely loving it with Steve's amps. It sounds phenomenal with both the Lincoln and the Impala, and I have a feeling it'll sound great with the Mercury as well. I also tried the Impala with some other American Voiced speakers like the Eminence GA-SC64 12", 1028K 10", Weber 10A125, 10F150, Jenson P12Q, and they all sounded really good. This amp really straddles both sides of the pond, and sounds phenomenal with both British and American speakers.