The cachecard is worth it regardless of how much recording time you have in your box. Just the speedup in the guide is worth the $99. But don't forget it's also a network card.

The current batch of cards, rev 2.2, should work without a hitch.

I have my DSR6000 DirecTivo upgraded to 187 hours using a single drive (200GB Maxtor). I've made cooling mods to the case that look close to stock and I'm running the cachecard with 256MB (until my 512MB dimm comes in the mail). Running TiVo SW 3.1.

Bruno