Are V8's more expensive to maintain than V6's? (R129)

[AlexNJ89]

I'm interesting in buying an R129 and I'm doing some research on them. But my question is applicable to all cars I think.

I've found the 500SL V8 to be appreciating in value quicker and have significantly more performance, I've also been told the MPG between the 500SL and 320SL is pretty small.

But I have also been told the true cost of ownership between the two is that the V8 is a lot more expensive to repair if something goes wrong than the V6. Is this definitely the case?

Thanks