Waste of money if the idea behind this is enhanced performance of your system. Why bother with these low powered and over-priced antiques? Now, if you are doing it just for cosmetics or as a collectible, then that is about the only valid reason to get the discussed units.
As for Emotiva -- they gave up the last of their special values when they discontinued the LPA-1, so far as I'm concerned. Frankly, you can do better with pro amps so far as power output vs. value.
If you want Yamaha, they have some super pro amps that are completely transparent. Check out P2500S, P3500S, P5000S and P7000S. The P3500S, for example, is 350 x 2 into 8 ohms or 450 x 2 into 4 ohms, 20hz-20,000Hz, both channels driven. At $500, it's a much better value then the antique you are talking about, and it has a full warranty. Now, being a pro amp, it is a bit low in sensitivity, since pro devices expect a higher voltage line signal. But you can get a high quality interface/conversion box for about $50-$60 to mate consumer devices with only RCA out plugs on them to the pro amp. Or, ideally, if you want to have higher sound quality in your system, add a device like the Behringer DCX2496 or similar DBX unit, that will give you precision control over your speakers, and also allow seamless integration of main speakers and subwoofers, far beyond what any receiver can do for you. You would not need a conversion box here, as the DCX has pro level outputs to directly feed the pro amps. The input on the DCX has a very low noise input gain stage that is variable, and was designed with hooking consumer level inputs to it also, so you only need an adapter plug, not a conversion box, to feed it's inputs.
-Chris