I'm trying to install a Gruppe-S 3-port for my Evo X, and since the kit doesn't come with the vacuum hose... i need to know a size...

it seems like 3mm or 4mm inner diameter hose that i need to use... but can any of you guys who has done 3-port (gruppe-s, perrin, grimmspeed, etc) chime in and plz tell me what size of vacuum hose i need?

thanks!!