1. what the diffence in length and weight between AU/3.2L?
if the same, then go the AU as i would think they would be lighter....
2. get the whole reciprotating assembly fully balanced seperatly then all the parts (crank, flywheel, balancer and i think they also use a the weights of the conrods/pistons bolted to the rod journals of the crankshaft) balanced together.
3. what r u thinkin of using? ive heard people on this forum have had good success on the 4L's with the EMS 8860
4. i dont really know about an offset ground crank, it will reduce some rotational friction but will also increase stroke. you will most prob get more power but i dont really know if it would rev more. i have read about a 250 X-flow that was offset-ground 80 thou which brought it to 280ci
titanium valves, custom machined titanium "rockers", roller bearing camshaft tunnel(not the word im lookin 4...but cant think of it...), billet crankshaft, but the most important thing of all with these things is to win lotto before putting them on your credit card.........,
on a serious side, an electric water pump would help a lot. definitly rev better.
underdrive pulleys would also help but i would think they would need to be custom made for the 4L