imho there's absolutely nothing wrong with Jags using Ford
parts. are you gonna lose respect for Bentley too coz it uses VW
parts? Platform sharing is the way of the future so we might as
well get used to it now 
I respect Ford as a car manufacturer coz it has given us good cars
like the Focus and Mondeo, not forgetting Mustang. The Focus and
Mondeo have one of the best, if not the best, FWD chasis in the
world (in terms of handling). Why should jag be ashamed of using
parts and sharing chasis from Ford? Even cars may share
parts/platforms, they are able to behave differently.
Anyway back to the topic, in terms of class and prestige, i think
there's no way any BMW can touch Jag. Jag is known as a gentleman's
car, but for BMW? Not so sure about that. No offense to any Beemer
drivers here.