Dash lights dimming & cooling issues

[Ari]

I've noticed that my dash lights dim time to time in my SE-R.  Now it has an
older battery and a new alternator (just did it in the morning).  Also I
have the UR UDP and no audio whatsoever [I didn't hook up the radio yet
:( ].  I was thinking it might be the battery but the car seems to run fine.
However sometimes when I redline the car the battery + brake lights come on.
I have an aftermarket volt gauge hooked to the accessory fuse in the fuse
panel in the car.  It stays around 12.5-12.7v and sometimes drops to
11.5-12v.  Next I have some questions about the cooling system, I've got a
mechanical temp gauge.  Sometimes at a stop the temp goes to 195-205*F
before I put the heater on full blast, otherwise it hovers around 175-190*F
and at night it stays around 170-180*F.  My temp sensor probe is in the
bottom coolant line that runs from the heater core.  Also are the timing
notches in the UR UDP correct, after I run out this year old gas I tend to
reset the timing + base idle.  Its been about a year since I last driven the
car and it rocks, it is very very quick.