You should also consider the new Xray buggy. Its due out in a few weeks. The XB808. It looks like it has taken allot of the best design features from many of the buggies you mentioned and melded them together. Downside is its not proven yet. But knowing Xray and the way the XT8 performs I'm betting its gonna be a heck of a buggy this year.
Just thought Id throw it in. I didn't read the entire thread so if it was already suggested and dismissed, just disregard this comment.