Just thought I'd put in my 'tuppence worth'.
I use a Voyager 205, it does get very warm, and I have been losing my internet connection intermittently SO, I took the thing apart and cut a hole in the top about 2" in diameter. Then I fixed a redundant processor cooling fan to the top using 1" spacers. Running from a PP9 (9v) battery this very effectively cools the little beast and, fingers crossed, no lost connection yet.
It's not a pretty arrangement so you can forget selling it on Ebay later
but then what use is a router that won't route?
Actually, when you open the thing up (the necessary screws are hidden under the rubber feet) you realise just how bad the cooling arrangements are. No wonder they overheat.
Cheers,
Roger.