Anyone know of a speaker mod or upgrade service?

I see ads here all the time for electronics upgrades (particularly tube stuff), but does anyone know of a service that upgrades speakers?

To put this in perspective, I have an all-Linaeum home theater; the problem is that Linaeum themselves went out of business before HT hit it big, so they never actually made a center channel of their own.

Consequently, I was stuck buying an early post-buyout, Radio Shack-built center channel which happens to use a Linaeum tweeter.

Although it matches decently, it's definitely the weak point of the system; the midbass is particularly muddy, and it lacks the dynamic punch of the rest of my system.

I imagine that, since it is Radio Shack-build, the caps and woofers are complete junk. I'd love to upgrade it, but am far from comfortable with a soldering iron.

Of course, it may not even be worth it; I may be better off getting something that matches up decently with the rest of my Linaeum stuff (maybe a Maggie center channel?) so I'm totally open to suggestion.