Advice needed on new well pump & water pressure

I plan on upgrading two upstairs bathrooms (new showers) and would like to increase the overall water pressure. Currently have a 80+ foot well with 1/2 HP pump (5 year old) and water softner as part of the system. Water pressure has always been constant - we never run out of water - but nothing great. Plumber wants to install new 3/4 hp Goulds 18 gpm continuous operation pump. We also have copper pipes that have sprung leaks over the years so he is recommending 1" plex from the basement to the second level of the house. I want to do this right. Any and all suggestions would be greatly appreciated

Is your plumber sure your well can handle the larger pump?

Yes, he said he looked at the original spec when the well was dug (21 years ago). Does the proposal and equipment make sense knowing that there is Home Master Water Softener installed on the system. We noticed a drop in the pressure after it was installed 5 years ago, will improving the input to the "softener" make any difference in the pressure of what "comes out" ?

You are going to have a certain amount of pressure drop through any filter or softner. The more pressure you put in, the more you should get out. Get your plumber to supply a list of references from people who have had that particular "constant pressure pump" for more than 5 years. I am sure he won't be able to do this, so you should stay away from those variable speed pumps. They were designed for the manufacturer and plumber to make a lot of money on, and guess where that money comes from? You!