Nice review. Could you tell any problems with using a 8cm stem? That seems a tad short for a bike and rider your size. At 6'3", the 58cm would work for me but with a 120 stem. My saddle to bar drop is similar to yours thus I would also need quite a few spacers or need to flip the stem.
I was most interested in the ride characteristics of the R3 and you described them well. I guess there are always compromises. If a bike is that snappy it probably will be more harsh than one that starts out smooth. I want it all but the question is how much do I need? My Parlee Z4 is very smooth and a good climber, however it is not what I would call snappy. I love the bike and for 99% of the type of riding I do it is great. Just every so often when I stand or jump I wish it were a tad bit more snappy. Maybe a stiffer set of wheels would make some difference.
Good luck with your decision. The R3 is certainly a great race bike.