I never remember the N62B48 sounding like an Aero 8 when it was in the X5 and 550. Sure it sounded good - but not THAT good.
Sometimes cars are greater than the sum of their components - sometimes less.
Clarkson harked on about the Saab 9-3 just being a Vectra underneath - but the truth was Saab changed a huge amount - incurring costs and bankrupting themselves.
The story of the 9000 was even better - platform sharing with the Italians the car was crash tested "Excellent!!" the Italians shouted "Lets have a coffee and take the afternoon off".
Meanwhile the Swedes muttered under their breaths about things not being good enough - and the project divorce began.