i was wondering where i can go online to buy an aftermarket head unit bracket for my 04 wrx i want to put my deck in thanks

 

You don't need a different bracket. As long as your HU is made for an ISO-DIN installation, all you have to do is remove the existing brackets from the sides of the factory HU and attach them to the new one. If you are replacing the dual-DIN HU with a single-DIN one you will have to get a DIN pocket to fill the space.
You will also need a wiring harness adapter.

 

so for single din head unit..i just need to take the stock cd player out and buy a pocket?

 

Pretty much. You do need the harness adapter for the electrical side of the install, so there is no need to cut any wires. With the adapters readily available there is no good reason to do a "cut and splice" job.
Also be sure to connect the power antenna lead from the new HU to the harness or your reception will be very poor. The 04 has the in-glass antenna with a powered amplifier.

 

www.ebay.com

 

go to scosche.com and see what fits. i think this harness will work since it's '03 and up.

Scosche SU03B

hth.