I just installed an Eclipse tape deck in my 93 with the premium stereo. At low volume there is a hissing comming from the speakers. Any ideas how to fix it?

I have the same problem. I talked to a guy at a local stereo store and he told me that the "hissing" is from the factory amp(s). You can get a wiring harness that you can bypass the amps. And since your new head unit has enough power you won't notice too much difference in sound (if any).

I also found out that the more power the deck puts out, the more the amp hisses. If anybody just wants to change the factory deck, don't buy a high powered one unless you like an irritating hiss.