Our home has a large addition on it and i'm thinking of running newer lines throughout our original house that has copper. There are many bends at various points and some are starting leak (probably 40+ years old). The original part of the house would need 6 hot and 9 cold runs setup whereas the addition would need an additional 6 hot and 8 cold. There's two 3/4" main lines (one hot, one cold) that feeds the addition of CPVC. I'm curious if I switch over to use a home run PEX manifold setup just for our original house if that would cause a pressure drop on the addition side or pose any other problems. Additionally here's a rough diagram (excuse the resemblance to pre-school art) of what i'm looking to accomplish.
I realize too switching out the copper for PEX may pose an issue with the grounding of our house so that will be verified by an electrician unless anyone has any tips on confirming this.