This is what's on the Vector now, and it's ten years old and still working at the same pressure as when it was installed:
http://www.drillspot.com/products/1377776/Dayton_5NXZ9_Multistage_Booster
When I worked for a distributor/service company, it's the same one we used on all auto installs and stocked as a standard replacement. They tend to last 20-30 years as long as it's never run dry and isn't trying to lift the water.
Are these Stainless or Cast (went back and scrolled down, SS internals, cast housing)? I would assume SS to move RO water for 10 years and still going, but either way I'd spend that to get 10 years from either. Got 2 right now that are tired, thanks for the post.