Please remember the following:
As you all know I am in the business. I hold to a policy that states that if I didn't sell it, I won't install it. Many other professionals hold a similar policy. It's like bringing your own steak to the Outback Steak House Restaurant and asking them to cook it.
The web is a great resource for the DIYer.
If you bought it on the web and had me install it, who are you going to for on site warranty support? Not me. If you bought it from me, I'm there! The web doesn't have that type of support. Explaining that to homeowner is next to impossible so I don't do it.
The web merchant will tell you to ship them the pump and they will send it out to get fixed. Or you may wait while they go through channels to get a warranty service company to schedule an appointment. If they are busy, you will wait. Warranty claims don't get a lot of revenue so they aren't high on a dispatcher's list of priorities.
The value I add to a product I sell and install is generally greater than the perceived savings of buying it on the web and trying to find someone to install it and support you, the consumer.
Scott