Hi Texas Senior Member,
You have already received some spot on feedback, but some more:
"We are considering buying a Sprinter B, either RT or LTV. About pre 2007 or so they have a MB 2.7L and then a 3.0 V6 after that.
Are there concerns with either?"
YES, but in terms of the 5 vs 6 cylinder models, I don't think that it is any big deal.
"I read MB recommends a maintenence interval of 20,000 miles.
How much would I expect to pay for this service?"
The question is Sprinter cost vs the popular Chevrolet Express Van in total. The Sprinter costs Noticeably more after 1 or 100,000 PLUS miles, fact. So the next question is what do you get for the extra cost? Only you can decide this with your application. Both handle well vs the general Ford for example. So it is floor plan, etc.
Have fun shopping.
Bud