to upgrade the kernel, just search Synaptic for "linux-image" and install the appropriate one. You can leave the old kernel in place, and choose the one you want when booting, just to be sure it all works.
With BUM things you might want to disable or not:
apmd
atd
hplip
Theres also an app just called "services" under system-admin.
Using it, you can disable things like:
atd
klogd
cups
Have fun.
Do look and see what stuff is before disabling it willy nilly.