cw55

So a few weeks ago I went to start my car after letting it sit for a few days..... It did not start the battery was dead.
I charged it up, routed two wires form the battery to an easy part of the front bumper area, and connected it to a battery tender.
I then started to monitor the tender light and and voltages from inside my house.

Today the tender looked like it was really struggling to keep a charge on the battery the red light indicating a fully charged battery was just not comming on very often, and voltage from the tender was so very slowly creeping up.

Connected my fluke in line and had a 500mA draw took a random guess based off other threads here and pulled #56 20A fuse, Radio,SDARS, and it droped to about 19mA then rose to 35-25mA and then stayed there...

It is a 2007 Mustang GT base model, no shaker system and no my color and other stuff like that.

Yes, I also have been ejecting the cd and turning off the radio before shutting the car down.

Can any one tell me what is considered normal current draw?
I don't like the stock radio so replacing it is not a problem, but will that really fix this problem?
Why is the radio drawing so much current with the car off?
What is SDARS, could that be it?