Those lines going to the alda through the switchover valve are pressure lines, not vacuum lines.
But that doesn't matter, what Targa-NF said is still correct. My boost line was cracked at the manifold. I fixed it but cant tell you it made a huge difference, but I am only able to drive this thing around the block for now as i am still waiting for registration.
On the other hand. Checking the vacuum connections and lines IS something I can tell you made a huge difference in the shift quality of my 300d. Some PO put a bb in the line to the transmission and that lead to no vacuum to the modulator. Fixing that gave smooth even shifts. If your vacuum pump is bad or if you have substantial leaks it can do the same thing I imagine.