In my opinion, intake and bov's are just for sounds.
I got a K&N intake and loves the sound. I don't feel any gain from the intake though. So far, I've heard that COBB and K&N Short Ram provides the same MAF reading as stock? I'm not too sure though. And I think BOV's are ok if you have a catless setup.
If you're doing a downpipe, might as well get your hands on a Uppipe too.