X-Force are better than China Spec systems but can't compete with quality locally built stuff or Japanese systems. They are priced accordingly: between these categories.
Although: X-Force Varex FTW!!!
http://www.youtube.com/watch?v=7IXrLqesZfI
I think you'll find the Cannon to be loud and drone quiet a bit at freeway speeds but you're a young lad, I'm sure you'll love it! If the 03-05 WRXs are as sound insulated as the 06/07s, it shouldn't be an issue (not to you anyway, I'm not sure about your neighbours haha)