Upgrade to Variable Speed Pump

I am looking at getting the Pureline Prime PL2626 to replace my ancient bronze pump. My thought process for getting the larger pump is so that I can run it at a lower speed then the 1.65hp one and save even more energy while having the same flow rate. Below I have provided what I know about my pool. I am in the future wanting to add a SWCG to my system.

Here are the stats of my pool that I know:

1HP Premier 455 Bonze Pump

18000gl, 8ft deep, gunite pool.

It has one of those 2 in-one skimmers that is connected to the main drain that is about 24 Ft from the pump if you assume builder used all right angles 2in PVC below ground.

4 Return jets no water features on 1 1/2in PVC.

Hayward S244T sand Filter with 1 1/2in inlet and outlet.

I currently use a suction side sand shark on it own vacuum port