Hi!
I use this forum quite a lot for reverence, but seeing your question unanswered made me register.
I own a 2007 (MY06) Legacy (Liberty) 2.0R. I few years ago I bought a 2.5i UEL header here:
http://rallisportracing.com/If you have a oil cooler (heat exchanger) between your oil filter and the engine you will have very minimal clearance. I removed that part without any issues.
Mike (the guy behind those headers) makes headers especially for the 2.0R now. A friend of mine bought those recently.
He has knock sensor problems now. We're digging into that at this right moment, so please stand by for more info if you are considering buying a 2.0R header.
I can give you a lot more info. It would be useless if I would leave that here without knowing if you might consider buying a RalliSport header or not.
If interested you could check out my Youtube channel for video's of different exhaust setups with this header installed.
https://www.youtube.com/user/Rookbom79It's not professional, just for myself and to be able to share the experiences.