The 2.5L engines are heavy. considering the block is 5 inches longer. and the crank is near double the weight of the 1.8t crank the Early 924 76 to 82 had heavy cast iron 2.0ls. the 944 has 2.5L and 2.7L 8V engines and 2.5 16V and 3.0l 16V engines. I have seen some of the VR6 builds. pretty cool! I do like the 2.7t engines, I plan on swapping one into a 924/944 after the 4.2l is complete. I do want to do the AWD conversion in our Passat still. I will do some research on the gearing to see how well it would work with the 1.8t. if it will be to much off. then I will get FWD 6speed from a later A4.