I have the ALTA CAI on my R53 and the foam filter still works just fine but it looks like it'll need to be replaced sooner or later. Has anyone ever found a cloth filter that you can use instead of the foam filter? It seems like it'd be pretty doable to find a K&N or afe that would be the right size but I've kind of struck out on their websites. I can always just buy another foam filter from alta, but I thought I'd see if there were other options.
Vendor - Detroit Tuned 15 Years
Anything that uses the same ID as the foam filter will work for you, but I personally like foam filters more than K&N filters, they filter better.