I'm quite new to linux also - and i just reread my post, and find it not very clear (woops!)
1) Debian testing (or unstable) packages are not unsafe to use. I find Debian very conservative and I often run programs from testing or unstable to be a little more up-to-date.
2) I dont think you need to compile the entire kernel to install the nVidia drivers. As I read it you only need to compile some kernel interface files (= few files).
When I was in the installation procedure after it looked at the nVidia site to download (but didn't find my kernel) I just said yes to the next option (which I remember to be something like "compile kernel interface"
Before I started the installation program I had typed
because I read it on some other forum. It is to use the same compiler version as the one that compiled my debian kernel.