Or any custom kernels, really: 'make localmodconfig' Takes the pain out of compiling a kernel. You might need to create an initial ramdisk depending on your distro, or enable filesystem drivers for FAT32 and NTFS, but otherwise it will enable all modules that you have loaded when you run it. (I had been using 'localyesconfig' before, but this works much better.) Edit: though it doesn't really take the pain out of actually running a GrSec kernel. Random Firefox crashes, X11 responsiveness issues, computer refusing to power down properly... Ugh. I know this is because the applications (and the display server, and the init system, and...) are doing dubious things, but I need to use those programs, and they're not going to get fixed any time soon.
Alright, after getting several system crashes on non-GrSec kernels, I believe I have found the problem. Protip: a Pentium D is not just a Pentium 4 with two cores. If you want to optimize your kernel, check the CPU family in /proc/cpuinfo. If it's 15, your CPU is Netburst based, i.e. a souped up Pentium 4. But if it's 6, then the CPU is actually Core 2 based - and optimizations for Netburst CPUs are not a subset of Core 2 optimizations, they're incompatible and may cause crashes. (Repeat after me: premature optimization is evil...)