Router: Cisco/Linksys WRT160N (Rev.3) - DD-WRT v24 (Build 14896 firmware)
While this is a very crude mod, my WRT160N was running a bit hotter than normal with the DD-WRT firmware (antenna output cranked up to 85mw). So, a simple mod with a 2" fan soldered to the power connector a 1.75" hole, and some temporary pedestals until I go to the hobby shop.
The temperature was getting up to 90 degrees and while the router has cooling ports on the top and is perferated on the bottom plate, it's not very efficient on the cooling side. With the fan mounted below (pulling air out of the base), I measured a 21 degree F cooler temp on the body of the router with the fan installed and operating.
Overall, definitely a plus when modifying these routers with better and more adjustrable firmware and (soon to come) external antenna's to handle the extra power output.
Step 1: Open the WRT160N and cut a hole
You'll have to open the router (voiding the warranty) with a T8 Safety-Torx driver (the one with a hole in the tip). Once you remove the four screws on the bottom, it pops apart by simply lifting the top cover from the base (a dime can get you started if it's tough). Gently lift the board out of the way - no need to disconnect the antenna's as there's plenty of slack in the wires. Once opened, grab a 1.75" (1 3/4") hole saw and cut a hole in the mesh on the bottom plate. Run the fan wires though the mesh for ease of installation.