Why can't you just get something meant for the Liberty?

Plenty of posts on here detailing various exhausts and suspension upgrades people have done. The reason why things for the WRX are cheaper is because there are a ton of them on the road so companies can make it for cheaper. Not to mention it's a very competitive market for them. But you'd think if most of those are compatible with the Libs I'm sure more Lib owners would get that instead.
But check out JapanParts.Com or get yourself a copy of Hyper Rev to get some ideas on what's available (won't have much made domestically because it's just not a big enough demand).