Is there no need to do this, because if not, I'm perfectly happy with my DIR-655 (cept for the continued deauthorization/reauthorization of the Wii)
My DIR-655 started to die last night (the N radio went, then I started to lose channels on the B/G connections, until all was gone). I bought a DIR-825 today.
There are some things I like -- the dual band radios are awesome. My MacBook w/ 802.11n flies now, and all my other B/G devices have their own radio. There are some new features even in the factory firmware that beat the DIR-655.
The downside is the v1.01 fw is still buggy, and the 1.10 beta update breaks 802.11b (which I need for the PSP and an old Linux laptop I've got).
If you don't need 802.11b, and don't mind running beta software (that
can't be downgraded), and can take advantage of a pure 802.11n radio, then now might be a good time to upgrade. If any of those items bug you, stick with your DIR-655 until it dies. (Mine died when it reached 13 months old -- right after the 1 year warranty expired!)