DLC - go post in the Legacy forum.
The WRX owners are equally sick of filtering the non-WRX content. Split the forum. Give WRX it's own major section and have powertrain, suspension, and general under that. The r... , er, I mean dress-up folks can have a section too, if they want.
It's frustrating to find some cool subject line and then discover that it's some wacky 2.5 RS turbo drag racer deal with 20 lbs of boost, clear lens covers, indiglo gauges, and a neon light underneath.
Or better yet, give everyone his own forum, then no one can complain about irrelevant content.