If the XF is a variable speed pump yes you will save a lot of money. The XF comes in different models. The normal XF is a two speed motor that pushes almost 300 gpm per minute. I will only use that pump if I have a extremely large water feature on a residential pool.
I have been using the XF variable speed pump for over 8 months now on all my pools and spas. It can push up to 220 gallons per minute and you can adjust the speed of the pump from 500 rpm to 3450 rpm. Because of the way that I calculate my hydraulics on each pipe run I rarely have to use the highest RPM speed.

If he is proposes 2" plumbing on either of those models or even a regular 2 Hp Whisper flo you will have serious energy consumption not to mention your velocity in the plumbing is dangerous. This is how entrapment in pools happens. If your builder doesn't want to properly size the pipes than find yourself a new builder.

Hope this helps.

Thank you for the feedback Pools94. The IntelliFlo the builder proposes to upgrade to is the variable speed model.

I will for sure ask the reason behind 2" pipe and request the PB to consider upgrading the plumbing size.