The electrolytic caps in the crossover are about to go out?! Out where? Don't worry about this, the caps are not subjected to the heating/cooling cycle of caps in a power amplifier (unless you really overdrive the speaker on a consistent basis, if so, see below) and are sufficiently upgraded in voltage to deal with whatever amplifiers you might use with the TC-50 and its easy to drive too hard woofer and tweeter. Leave them as is and enjoy the sound. John Bau worked very hard to get the TC-50 and all of his speakers to sound right with the components he chose. The speakers were not built to cost considerations beyond the most extravagant, they were built to sound quality considerations. Each part was chosen for its value to the final product. Do not change out the internal cabling as it too was chosen for its value to the final product. If you swap out the cable, you will affect the crossover values by altering the LCR values of the system and the speaker will ultimately sound different, and not likely in a good way. Do not change the internal stuffing or the external felt blanket of the speaker. The Spica line worked the way it did because Bau knew what he was doing. Bau did make a concession, late in the life of the company, to those who wanted a bit more volume out of his speakers by offering upgrades to air core inductors which will have less saturation at high voltage input levels. The difference is very slight and only of value if you consistently border on overdriving the Spica/Audax woofer. (The drivers are no longer available, be careful.) The inductors are the only thing I would change on a Spica and you'll have to know (all) the correct values for the stock inductors before you make any changes. Just sticking some audiophile approved inductor in the crossover will once again affect crossover values, particularly if you drive the speakers hard as inductor values and voice coil inductance and resistance increase with heat slightly shifting the crossover point of the drivers. My advice is to leave the speaker dead stock as they came from the factory, don't think you can improve on perfection and stop believing what that shop told you. If you want to alter something, neuter your cat.

(I own a pair of Angelus and sold Spicas for several years. Nothing sounds like these speakers other than real music. Sound Anchor stands work best with the TC-50 in my experience. PlastiTak or screw the speakers to the stand and use the spikes. Use a tape measure and a laser pointer to do the set up. Very small increments make large differences in the sound you get. Tilting the speaker forward or backward with the leveling spikes will also change what you hear. Try a one third placement into the room.)

http://www.nsmaudio.com/brochures/basicstsetup.html

http://www.gcaudio.com/resources/howtos/speakerplacement.html

More links at the bottom of the gcaudio page.

I had TC-50's for years too and I don't know if it was the caps or not, but in my opinion they gradually lost a lot of their zip and dynamics. If it were possible I'd go with your dealers rec. and get them upgraded/replaced. I did mod mine way back with MIT wire internal wiring and that was a worthy endeavor as it added bass extension and even more focus. I know a good component will keep going for a LONG time, but they do age and suffer a gradual sonic degradation.