The 80s get a bit lower and can play a bit louder. The QUALITY of the audio is pretty close. You don't give much up with the 60s Have you checked to see if there is anyone nearby who can provide an audition?
Also, and this is just me talking, a 12x20 room might be a tad small for the 80s. Assuming that you have an 8' ceiling, your room is 1920 cubic feet. The 60s are recommend for 2000-6000 rooms. The 80s are recommended for 4000-8000 cubic feet. All things considered, the 60s might be your best choice. Easier to drive, a bit less expensive and REALLY great audio. I don't think you would miss the 80s one bit.
