For a 55, I would actually rather get an xp3. I found out that the xp4 is actually too tall to fit under my stand comfortably so I have to put it outside. Also, the xp3 and xp4 come with the same amount of media so you will be able to fill up more media baskets in the xp3 than the xp4. The xp4 is quiet so its fine outside but it just makes it not look as neat.
Gotcha. Yeah i'm gonna get the xp3 i think cuz i'm gonna keep my hobs running too.