Well on TFSI both transverse and longitudinal are mounted the same way round, and its the same way as the A4 anyway. The TFSI K04 fits the A4 easier than it fits the A3, its just a bit annoying that flange catches the engine mount.
Also, there is no longitudinal TFSI K04 car, which is why theres the mounting flange issue catching the engine mount. TFSI K03's use a smaller flange and this clears the mount just fine.
The aftermarket manifold issue is a real concern for me, i simply couldnt be ***** ******* around with manifolds, which is why my K300 is mounted to a ported standard A4 manifold.