Woa so that upgrade for the older Sierras are a bit more touchy I see... Hmmm... :\ Oh well, doesn't seem too insurmountable, some weird things though, glued mesh, binding posts...
Can you still manage to switch the binding post cables without destroying the mesh? Or since it's glued you'll pretty much have no choice but somehow ripping it off?
And I'm guessing the goo gone dilutes the glue and then it's easy to just tighten back the posts once the crossovers have been switched?
Those clips on the tweeters/drivers are very practical! Didn't know those things existed, looks much easier than soldering the wires!