probely not a good idea to shout out about that
Iv only tried 6 and 8 but i find 8 is better, theres not much difference between the versions but genrally the latter ones are oviously better, as a lot of the tools and ways of doing things have been upgraded and improved, for example i find maping in 8 easier then in 6, and plus in 8 you don't need any aditional plug ins to do so.
A lot of the newest and latest tutorials are for use with the later maxes aswell, so it helps to have an up to date version, plus lots of people on here use the newest versions so if you get stuck with anything we can help you out.
The Brazil plug in doesn't work in 3d max 8, but you can use som other great plug ins like V-Ray and Mental Ray, both of wich (in the right hands) are just as good if not better, HERE is render i done with Mental Ray using an online tutorial to learn the ways of creating scenes and shiny textures.
Cheers