S14 Weak Electrical System?

[Sills]

Hey, I imported a Nissan S14 Silvia several months ago and when I got it everything worked good, However after driving it for a couple months I started getting strange responses from the electrical system.

The first time I started getting these issues was actually after I got my vehicle back from my mechanic who had installed side marker lights and DRL's so that it could pass safety. However that might just be a coincidence.

The primary symptoms are-

-Radio will make a high pitched "Squeal" which will increase in intensity with higher volume on the unit as well as rising in pitch with the revs.
-Hids will flash and die when coming to a stop, wont turn back on until I physically switch them off, then drive at around 2k rpm and put them back on. However if I have the car parked and idling and I put the hid's on they will run until the car starts driving and comes to a stop again. Also the left HID sometimes wont even turn on. All the dash lights dim during this aswell.
-Most recently the car cranks slowly and its sketchy to start it up.

This is not due to the DRL/marker lights as I have them removed now since passing safety. Also the alternator was squealing for a while and I believe it had been seizing intermittently as there was a strong rubber smell coming from it at times and the belt has lost a couple ribs. I did recently replace it with a Sr20det alternator, it has stopped the squealing however not the issues.

I have not tried using a different battery however the one in it is a 670cold crank amp battery purchased under a year ago that I used to run in my daily driven Honda Accord Turbo.

I have also pulled all fuses and they all seem to be fine. However my Climate control fuse has burnt out twice since owning the vehicle? It was slightly abused driving around in Canadian winter on several occasions and thats when that happened however...

Any suggestions are greatly appreciated, and will save my future hearing c:
Thanks!