check for any signs of damage to the cone, surround, spider, pigtails. next is check if the cone move along it's entire excursion length smoothly. if those points are ok, there shouldn't be any problems with the speaker.

the 4-channel amp can power the macroms and a subwoofer. if you plan on using a powered tube sub, then the extra 2-channels of the amp can be used to power your rear speakers.