to be fair to the pierburg i found out mine had a split vac pipe right at the back only visable once removed which was why it ran like a pig.
before it must have split it ran beautifully and was fairly quick.
the only thing i miss from it compared to the weber was the auto idle adjustment which kept the idle around 900rpm
the weber kind of needs to be set around 1000rpm so when all the electrical loads are turned on its around 900rpm as it has no self idle regulation, just a screw against the throttle.
also having a choke on the weber is a novelty
dont forget to turn it off when warmed up as its amazing how quick it will use fuel if you dont