I'm allowed to answer the 2nd question! yes it would make a difference both to your production time and your TDS level after the RO.
I bought one the other day from craig, I have a 300 GPD ro from pure freedom. I have know idea what my water pressure was/is. It was taking 5.4 mins to produce 1 litre of pure water. It now takes 2 min 1 second to produce 1 litre of water, Only fitted it yesterday, very happy so far (although if I am honest I would of liked it to be faster )