Well I tend to agree with these 2 gents. The platform which Audi launched with the A5 in March 2007 was the B8, which was then used as a base to develop a family of models, including the new A4. BUT they are about 99% NOT going to be the same for about 100 different reasons. The A5 for instance was said to be designed to house the engine as near to the bulkhead as possible to try to offer excellent handling even in FWD format, to "resemble" a RWD car's feel. The A4 had totally other objectives like space for the kids and the luggage, for instance, so they are not gonna be the same front ends.