1999 Other Mitsubishi Models Alternator is hot?

In the middle of a 2-hour drive, my maintenance free battery started smelling strongly of sulfur. Upon inspection, I found all 6 cells to be bone dry and the battery to be hot. I added water and drove home another hour. Battery tested good at Autozone (so did the alternator supposedly), but I replaced the batt. Anyway for fear it would die soon. The next day, after spotting liquid on top of the brand new battery, I removed the alternator and this time, the alternator tested bad (bench test).

Took me a couple hrs to get the old alternator off, and the autozone guy said, "wow, that's hot". I mention all of this because I still think something is wrong. I'm not sure how hot an alternator is suposed to get, but the new one seems to be getting hot too, and there is a strange sound that comes from the engine when the engine is under load. Best way I can think to describe it is a high-pitched electrical sqeal. The sound may be the "gator belts" I was talked into at autozone. It's an ugly noise.

I just tested the battery voltage with my trusty multimeter per the manual and got possibly strange readings -

13v when off
14.3v at idle
14.3v at 1500rpm or 2500 rpm (holds steady)
when I let off the throttle voltage drops to 13.5v and then back up to hold at 14.5v

Is this normal? Does it sound like there's something wrong other than the alternator that may have even cause the previous alternator to go bad?

On a related topic, I've owned the car for a little over a year, and ever since I bought it, the radio cut out randomly. The problem got worse recently to where it would cut out when I started off to work in the morn, and wouldn't come back on until I was just pulling into work. Very frustrating. Now that the alternator and battery are replaced, the radio is working like a champ - has not cut out at all. Also, I last night I noticed the lights dim a little and there has always been a sort of surging to the engine that is not cool. It sort of cycles slow to fast at random. A lot of cars I have had done this and this has always nagged me.

please help!