well, there's two, first off.
Nemesis kernel is just a kernel from XP with added features that I've been playing with, I believe it's build 2650, NemesisXP is a copy of windows that has lots of bloatware installed such as clock utilities, tweakui, officexp, and some other programs. It's fast as hell, however, so it adds some tweaks, too. It's NOT good in car and you're better off with XP Pro SP2. Nemesis is fast in windows, but it's not ultimately much faster
1995 Ford Mustang Convertible DSATX | Shuttle XPCSN41G2Bv2 | 619GL-70NP | CF 1.6 (which is still unusable in the car!)