So i just picked up an aftermarket cd player "Sony CDX-M9900" and anyway i got a few questions. The cd player came with a braket thing that slides over the cd player case that you use 2 keys to remove, in a WRX you dont use that bracket correct? I just screwed the CD player into the factory brackets. Also i got an impreza wire harness from specmo and just matched all the colors on the wire harness i picked up and the harness for the cd player and soldered them all together. Last it shows to hook up the power from the batt and ground it somewhere on the car but the harness i picked up already had power and ground so i cut off the connectors and soldered the wires to the harness. Sound about right? BTW this cd player is crazy.
http://rds.yahoo.com/S=96062883/K=CDX-M9900/v=2/SID=e/l=IVI/SIG=132020rm3/*-http%3A//www.rondevries.nl/catalog/images/cdx-m9900.jpg?osCsid=0f7fb3aabe4b64d49137ec30427d7b03
http://rds.yahoo.com/S=96062883/K=CDX+M9900/v=2/SID=e/l=IVI/SIG=12bbc7pgo/*-http%3A//www.sonyproductinformatie.nl/s2004/pictures/detail/CDXM9900.jpg

...The cd player came with a braket thing that slides over the cd player case that you use 2 keys to remove, in a WRX you dont use that bracket correct? I just screwed the CD player into the factory brackets.
Correct (btw, it's called a "DIN sleeve").
Also i got an impreza wire harness from specmo and just matched all the colors on the wire harness i picked up and the harness for the cd player and soldered them all together.
Most probably correct, but I would double-check by looking up the various OEM wire functions in the link given in the forum sticky, and comparing with your Sony manual.
Last it shows to hook up the power from the batt and ground it somewhere on the car but the harness i picked up already had power and ground so i cut off the connectors and soldered the wires to the harness.
Should be fine as long as the HU doesn't draw too much power. From looking at the Sony's specs, it looks like it draws 10A or less, which should be OK.

In the manual its called a bracket so thats what i called it, ty.