I'm running an Alpine 9855 head unit with stock components otherwise and I've noticed a lot of heat coming from the stock amps in the dash, near the doors. The heat is so much that I can feel it through a pair of jeans! The A/C will mask a lot of the heat, but I don't always run the A/C.

Anyone else have this issue? The radio was professionally installed and they said they ohm-matched the head unit signal to the amps...

 

You're likely clipping the hell out of the input section of those amps with the Alpine. Without getting into some crazy electrical garbage, just try to live with it until you swap those out, too. You know you will eventually.

BTW, how can they "ohm-match" the signals? Did they use speaker-level inputs with an LOC, or did they use the pre-amp level outputs from the Alpine. This is important info that may help us to solve your problem.