I'd think they used a high quality amp from what I know about RBH/Aerial, but amps inside sub boxes just is a poor location. They tend to work until they don't, so if working without issues it's just a matter of time...it could well be a very long time before it does go. I also suspect the owner of such an expensive sub likely didn't abuse it. If the amp did have issues, they can be removed without too much drama and sent out for service with reasonable transport costs (compared to the whole 130 lb sub particularly

).
You are buying the sub without demo, or is the ordering online referring to service?