Well i'm about to pull my motor for a rebuild and I was wondering what parts are....removable?

As far as engine wise I have to pass emissions but has anyone removed all that crap and passed? I would assume the airpump is required to work with the cat (stock exhaust still except for DP).

Off the engine however what can I kill? Car is all stock for the moment. Things like a new intake and in the future V-mount are planned but anything else to clear up the bay?