Should I replace capacitors in Active ATC's??

according my ATC dealer - the caps in ATC ampacks are military-grade and should last well over 10 years. i was wondering the same thing a few weeks back and that's the response i got.

were i to replace them, though - i might try the DNM slit-foil caps.

Lazarus, I know nothing of this slit-foil cap and looked for it. As far as I can see, this technology is available only in a 10,000uF/63V. cap.

Mooner, probably the sound of those speakers could be improved by replacing the caps with higher-quality ones. There are lots of threads here on that. SEARCH.
.

You'd only need to replace electrolytics. BUT, 5yrs down the line, it really may not be necessary yet. Have you detected any loss of clarity, dynamics, "closed in" sound, lately ? If not, I wouldn't worry UNLESS you simply wish to try to improve the sound (the change is reversible, anyway).
BTW, if you're not a diyer I suggest you get a hard-core hobbyist or a qualified electrician to do it.