I guess one question that needs to be asked is: "Will they be used during Winter?". Some handle it, some don't but the spec sheet should show the acceptable operating temperature range or maybe a call to tech support is needed. Butyl rubber surrounds definitely handle more abuse and last longer than foam, so that would be the first thing I look for. If they won't be in direct sunlight, I'm not sure the temperature will be an issue and if they will be, make sure to manage the clients' expectations for lifespan.

I try to avoid exposure to direct sunlight except in early Spring or late Fall and if it's unavoidable, I try to avoid exposing the face with the drivers to sunlight. For the rest of the year, they're left in place- I don't remember seeing any instructions to remove these during the worst weather.