Hi intune,
Keep your Kenwood if it's still working well and get the M60's. You've got lots of power to drive them. Indeed, back in those days manufacturers were much more fastidious and honest about stating the true output power of amplifiers.
Nowadays, you almost never see specs like "power bandwidth" because output power is measured at a single frequency--1 kHz--(it results in bigger numbers) rather than over the full audible range. Even worse, many brands of home theater receivers advertise the output power with only one channel driven, which is very misleading.
If you haven't had trouble with the Kenwood so far, you can expect to likely get five or six more years use from it.
Regards,
