As you noted, you're probably going to have to get new surrounds for the woofers. In addition, most attics are very hot places during the summer months. I would think that the capacitors in the crossovers are pretty much shot, so they'll need to be replaced.
Finally, any parts of the speakers that might react to the hot temps should be looked at. And this might include any internal bracing that may have been affected by the temps...
-RW-
Finally, any parts of the speakers that might react to the hot temps should be looked at. And this might include any internal bracing that may have been affected by the temps...
-RW-