-
the flow rate is limited by the weakest part of the pipe run.
Which is what that is normally - the pipe is bigger on the other side of the outside stopcock.
You might think that standard 22mm domestic piping would be a barrier to increasing pressure but I can tell you from experience that if you improve the connection between the stopcock and the rest of the house your water
pressureflow will improve.
Probably, if it looks sad.
No, I don't think so, the flow rate is limited by the weakest part of the pipe run.