At least in my machine, WB runs pretty fine, the resource usage is decent.
Sadly, there isn't any way to use any other msstyles without patching Windows (damned digital signature <.<), but once you have it patched, you can install any msstyles, and since the DLL that loads them is just a modified version of the original, it doesn't take any extra resources.
The bad thing is that, by default, WindowsXP's UXTheme system doesn't allow fancy things like transparent windows/borders/menus/etc, something that WB (since v5.0) DOES allow... |