When i rev my engine, the boost goes up to 0 bar and then to vaccuum, but the needle rises back up a bit as the revs are going down.

Does this make sense at all?

I cant say that my car was'nt like this since i got the gauges put in, but this is the first time ive noticed it. Is this normal?

 

yes this is normal

 

mine does the same, what does the vacuum level out at?