I ordered the accessory guage package for my 04 SSR, from my local dealer, and had them do the install just before I left Austin on an out of town assignment to Atlanta.
The voltage guage works, but the other 2 guages (gallons per hour, and transmission temperature) do not! Since I was literally leaving town the next morning, my Austin dealer told me to just take it into a dealer in Atlanta once I got there, and have it replaced. The Austin dealer told me that they had had one other guage package before mine arrive DOA exactly the same way. They assumed a bad batch.
The Atlanta dealer's service advisor though told me something different after he examined the failed installation. He says that the Austin dealer's tech had accidentally somehow shorted the unit during the install, and THAT had caused the failure.
I don't know which dealer is correct, but be warned: you MAY have a problem. It is covered under warranty of course, but it's still a major inconvenience, as it requires a minimum of TWO visits to have it corrected: one visit to diagnose the problem, and a second one AFTER the replacement guage set comes in (unless the dealer happens to have one in stock - my Austin dealer did not, and neither does the Atlanta one).
If any of the rest of you order one of these, make sure you discuss proactively with your installer what I wrote above, as there MAY be some common error that it is easy for a technician to make on this seemingly easy install.