vacume

Hi guys Looking at changing my vacuum hoses before i get my remap and turbosmart dumpvalve and not sure what size i would need to get as ive searched and some say 4mm and some 3mm. So do i need 4mm or 3mm hoses? I found the below on Forge's site would 3metres be enough to change all...

has anyone removed that little black box off the top of their rocker cover?? i think its a vac resivior but i want to delete it... any suggestions?

I'v got a split hose going from the charge pipe to the N75 valve, Does anyone know if there is a upgrade kit for this if so who sell's it. I'v looked on Forges website but there's nothing there. The hose that has split is the top one of these two