how to set up a mix from stable/testing/etc

[Christian Schnobrich <schnobs@babylon-kino.de>]

Hello,

Woody's spamassassin (2.20) provides me with a hit rate of about 60%;
partly to increase this, partly because I'm curious about that fancy
Bayes filter, I'd like to have a more recent spamassassin.

But how?
I'm a little shy of installing tarballs -- I'm afraid this would give me
trouble when eventually I want to install the .deb package.

Leaves me with getting it from testing; I regularly see posts on this
list where people claim to have a mixed setup from stable / testing /
unstable, but I found no clue on how I could do this myself.

Could someone please provide me with a few keywords for a google search,
or point me directly to the appropriate documentation?

cu,
Schnobs