RE: The Official Traxxas 4wd Slash Thread...
Found this on another site
"Suspension geometry is new and specific to Slash 4X4. Nothing wacky, just good design. The engineers spent a lot of time getting the roll centers and such dialed in, both on the computer and with real-world testing. It was fun to see the various prototypes gradually zero in on the final design. Smart dudes in engineering, I'll tell you what! Slash 4X4 has the same Ultra Shocks as Slash 2WD, but with new progressive-rate springs (they're stiffer).
It'll be under $400, but the price hasn't been dialed in yet.
Expect these bad boys to be in shops for early December. C'mon Santa!"