so im wanting the 3.5 pulley from ZZP. They recommend their Downpipe before going to a 3.5 pulley. My question is which Downpipe would I want to get? what size? and would i get the 02 Bung not sure what it would do... Im in cali so emissions is on my mind. I also decided i might as well get the U bend delete as well but the 02 Bung option is there again... I dont want to pay for anything that i dont need. Help!