08 WRX and LGT boxes are very similar, but slightly different. I know the fronts are interchangeable because I had swapped an open front box from my WRX into the LGT once I got an intake. But the LGT rear section has a snorkle, and the WRX doesn't. Im also pretty sure the mounting points/brackets are different.
I cut up and butchered an airbox, but bought a new one off 3gwrx.com to have a "go back to stock" part if I need it. I might have an extra rear half if you need it, but I'm guessing you only need a front. You can say I'm a bit of a freak about hoarding parts and not selling them. But I don't wanna have to buy it again if I ever need to swap back for any reason.
I think I picked mine up used (basically new) from some kid who saw dollar signs in a "useless piece of plastic" after he bought himself an intake. I paid $35 shipped or something.