Jdm spliters can be hard to find and kinda expensive. A company makes a aftermarket one that fits it well can't remember the brand of the top of my head though
do you also have a v7 IC? you probably don't want the splitter unless you have an IC that covers the opening, otherwise you won't really be directing the air to the intercooler as you will be directing some around the intercooler. I have a JDM scoop and I haven't installed the splitter (I have a JDM splitter) because it really wouldn't work well.
these guys seem to have it, I think I bought mine from Vivid http://www.rallispec.com/prod_aero.htm RST-9085kit WRX MY'02-'03 (Ver.7) $125
I agree about the hard to find part, but they are cheaper (even new) than the aftermarket options that I have found (GT Spec and Zerosports). I still currently have the stock IC but am planning on an upgrade in the relatively near future, whether or not it will be the v7 unit I am not sure. Any thoughts on whether or not the v7 splitter is the best choice with an aftermarket TMIC? Thanks for the link, I have found a few places that have new ones, but I was hoping to run across a used one to save a few bucks. The only cheaper place I've found is here: http://www.cvrmotorsports.com/store/index.php?target=products&product_id=3373 Thanks for the comments guys, let me know if you decide to part with your v7 splitter.
I think I paid alot more for mine from vivid a while back, and when it originally came the rubber skirt was not included, I remember having to call and point out what the website said to get them to ship me the skirt. both the skirt and splitter came directly from Japan in subaru boxes. I personally have been looking for a deal on a V7 IC, but there are not a huge number around. From what I am told the stock IC's of any sort are really not the most efficient heat exchangers and that the bar and plate IC's are a better choice. My advice is to do what you want.