Dave,
May want to check this thread and especially post #5 from Evan (Waterbear).
http://66.129.2.151/pf2/showthread.p...hlight=uprated

All I can say is Watermom is using a Hayward Superpump, inground model SP2600X5 I believe, 1/2 HP, and it seems to work just fine. She had a problem with adequate suction for vacuuming for a bit but once a good backwash was done that issue was solved. Filter was plugging and I think at the time the pressure gauge didn't work. In any case, stay away from those blasted screw on lids. After some time they may be a dog to get off. In your case I wouldn't consider a 2-speed unless you plan to upsize your filter. My opinion. Maybe Evan will chime in as he's loaded with experience and good info.
Al