can a new amp amp tame my speakers?

A used Butler 2250 would sound good with the Infinity's, I would think. Lots of power and smooth top end.

Found some reviews on that, and it does seem like a nice match. A little pricier than I was planning on, but not totally out of the question used, there's a couple here used for $1750/1800. The Odyssey is still leading the way though...we'll see...
Thanks again

Just a thought:
http://app.audiogon.com/listings/solid-state-conrad-johnson-evolution-2000-2013-02-12-amplifiers-19464

Oh Boy, more choices :) - at least that is a loal pickup in PA, so no real temptation there. I know nothing about tube amps, or the maintainance involved, whereas the Butler supposedly gets around the maintenance issue by not driving the tubes to the max...

It seems tubes would smooth out the highs, though, is that the consensus? I'm wondering how much of the objectionable highs I have is from the amp running out of juice. Does that make the speakers sound that bad, and therefore, a 'real' amp with 'real' current would eliminate the problem? Or is it a speaker issue that just comes on at high volumes, and needs an amp that's softer in the highs to reign in a problem inherent to the speaker. As I've said, I have no objections to the sound at low-mid volumes, just when I'm cranking it up. Perhaps the ribbons in the Emit tweeter are heating up due to the amp running out of power, and that's why they sound bad, or will they do that at high volumes even with more (enough?) power?

My thinking is, if the speakers are inherently flawed in that area, and even a 'good' amp doesn't fix the issue, then the speakers needed replacing anyway, and anything I get would need a better amp than I have now. So a good amp now (first) isn't a waste. If getting an amp does fix the problem, then I've saved a significant outlay on new speakers. Klaus at Odyssey swears up and down I'll be blown away by what my speakers sound like with his amp, even though the wpc rating is about what I have now...

I suppose I'm not really looking for a amp that's 'softer' in the highs to counteract the speakers, but rather hoping that the objectionable highs I have now are because of the amp I have now, and therefore a better amp will eliminate the problem. I don't want to correct a speaker problem with an amp, but correct an amp problem with an amp.

I haven't actually heard the combination, in fact I'm not sure that the Kappa's I heard so long ago where the same as yours.
I do seem to remember that back in the day the Infinity IRS' (along with the Wilson Wamms) were the top of the line, most expensive speakers going. I could be wrong, but I think those IRS' might have used something like the emits that are on your Kappas. This is a long time ago, but I seem to remember that tubes were the only way to go with the IRS' (the bass panels had their own ss "servo" amps built in), and c-j tubes were a popular choice for them, but even with tube amps, some used to cover the IRS' tweeters with tissue paper to attenuate the brightness. In as much as that might seem to be an anathema on a speakers that cost around 50-60$K in the late 1980's, it was pretty effective. I even have a friend that uses the same fix today on some old Linn speakers.
Those IRS' midrange/tweeters did some magical things, and are still sought after today, but obviously they weren't perfect (at least IMHO).
I believe your speakers have a nominal impedance of about 6 Ohms, but I have no idea what the minimal impedance is. The use of self powered subs might be very advantageous with them, but that's purely speculative on my part.
As well as I can remember (not very well), I remember the Kappas as being OK, but found other alternatives preferable. You might very well disagree.
The c-j I hyperlinked is actually a tube/ss hybrid, seemed like a calculated safe choice. YMMV.