Re: Crankcase breather filters ???
I've seen em, them baby little filters, look cute. I think the main purpose is for show, another shiny bit for the engine bay, so they wouldn't be too easily hidden either.
Also some upgraded air filters/intakes do not have provision for the crankcase breather so either you need to drill and make it or put one of those filters onto the end of the pipe.
I don't think it would make any real performance difference, except that it would probably greatly reduce the air intake getting clogged up with that black gunk.