Looks like a pretty good deal to me, rubber boots on ball joints should have kept the grime out of them even though they have now melted, looks like most of it just needs a good clean up and inspecting for any cracks in the plastic.
Rear shock mount from the Avante 2011 will bolt straight on, it's a different much stronger design with different mounts to attach it to the chassis. You also need a motor mounting plate, again the Avante 2011 one will do. All these parts are included in the Avante 2011 press parts bag.
If you want to fit ball diffs and/or centre one way, the parts are available as an upgrade pack for the new Avante, part number is 84257 for the complete set.
You might also want to replace the metal front uprights with the new machined ones, the original cast ones tended to break if you hit anything.
Tamiya have the 2011 Avante manual here
http://www.tamiya.com/english/rc/rcm...8489avante.pdf so you can compare parts.