Its only an extra two feet and a seat. How much weight can that possibly add? That car is quite heavy anyway. I bet the extra bit does not slow it down too much. I am half tempted to throw in a bid. If the car was a bit closer to my location I would try to get it. We are going to have another child, that make three. The extra seat would be a welcome addition. The back seat of our 123 is going to get pretty small with three childrens car seats in it.

By the way which mercedes do you think has the widest back seat. We have about 53 inches armrest to armrest in our back seat. Need a couple more inches.