A 6.3 is a comparitive bargain! And the 6.9s are a steal! Sadly repair costs are not (hence the high dumpage rate), but still far cheaper than a leaky 600!
Common is the senario where 6.3 and 6.9 owners know they're an awfull lot of car for the money, but cannot afford their up-keep. So rather than sell, they leave them in a corner of the garage (if the car's lucky enough), grovelling on all fours....