Disagree. Since your combo is a 2x8, the most logical ext cab would be another 2x8, but at the very least, you should be looking at cabs that are close to the same output as the 2 8's. Anything bigger, like 4x10's etc, will completely render the 2 8's useless, and in constant danger of over excursion. You always want to closely match any 2 spkr cabinets, so one is not over powering the other, exposing it to danger of blowing. Much info available right here on this site.