We have looked at a Sleep Number (we are both taller so a split Cal King is tempting) and are considering a Purple (just split King) but the massage feature in the GhostBed is interesting. Since the massage feature seems to come with the base, how does it work when it comes to the mattress? Since the mattress has a 100 day return policy and the base does not, if we don't like the mattress, can we return it, buy a Purple or a different mattress we like, and have the massage function still work? Any advice on this process (adjustable beds/mattress suggestions) would be appreciated.