Since your pool is roughly double the size of mine and assuming approximately the same turn over period you will need to move something on the order of 20-30 GPM. As a data point my pump uses about 250 watts at 30 GPM and 140 watts or so at 15 GPM. The actual power consumption varies a little bit in operation. I find that it climbs a little as a function of air temperature. So I may start out the morning at 125 watts and climb to 155 by mid-day when the sun shines directly on the pump. By late afternoon the power consumption drops back to 140 or so.

I originally looked at 2 speed pumps and decided that the flexibility offered by the IntelliFlo was sufficient to offset the price difference. It makes sense to me that by moving the water as slowly as possible I get better filtration and the long duration filter cycle allows for continual mixing of the pool water during the course of the day. This seems to lower consumption of chlorine even here in AZ where the sun is very intense.

I purchased all of my equipment online (pump, heater, SWG, filter, and automation system) and had no problems. I have used all of the following vendors:

Paradise Pool
American Best Pool Supply
Online Pool Supply

I purchased the bulk of my equipment from Paradise. The pump at these vendors runs from $1250-1325.

When I installed the pump I upgraded to a 20 amp service and changed the plumbing to incorporate unions on either side of the pump. Other than those minor modifications the pump replacement is a fairly straight forward one for one.