Where do you find a STi wing to hook on my RS?
something less than $500 bucks

Real or replica? Replicas V5 wings are pretty easy to find for $250 - 350.

I didn't realize until recently, but the USDM RS coupe wing (the taller one) is the same as the STi Ver 3/4 wing.

Edit: D'oh, you have the newer body style. Same difference. Try:

http://www.writerguy.com/primitive/wings.htm
http://www.gruppe-s.com/Subaru/subext.htm

Google can provide others...

I'd reccamend getting an ABS plastic one, fiberglass suxorz.

the guy at my dealership said he can hook the wing up painted for about $400.

I also advise learning how to spell better than I can!

I also advise learning how to spell better than I can!

Heheh... well, at least you realize it. Run-ons and bad spelling usually make bad first impressions. "Ah, well, he can't even spell 'Impreza' so I'm not even going to bother to respond." <== I've thought that a lot of times.