Here’s a guy who manages to modify his Linksys 54G router into a super router by installing a CPU heatsink with an external fan, adds super-long 9dB antennas, and aftermarket firmware DD-WRT to overlock the darn thing as much as possible.
I actually personally using one of these routers with DD-WRT, overclocked a bit, but this hack certainly will allow you to be on the very bleeding edge of router hack