phpsuexec is just a hack Nick got from http://www.localhost.nl/patches/ and he modified it (in bad ways) to allow it to run files owned by other users/groups for the global Cpanel scripts in cgi-sys. Oh well. Anyway, that patch alone isn't really so bad, depending on what you do to it. Basically, Cpanel just does a couple of different things for it and keeps it working for Apache's newer versions. Some of the mods, I don't agree with, but that can always be changed or left out, if you know what you're doing. Always be careful when modifying or using any code that is suid/sgid root or any other privileged user. As other's have suggested, check out suphp.org instead.