Saved the money and dont get the twin frozr. Just unlock and oc past the twins specs. Always nice to have the backup bios switch just in case of a bad flash.
While the Twin Frozr III may be expensive (I haven't checked), the Twin Frozr II's are cheaper than the reference cards in many cases. The reference cards are a lot hotter and noisier than even the Twin Frozr II, and may not be desirable for crossfire.