After receiving only one key (identified by car as KEY NO.2) with my BLS I was quoted something like £80 for a new transponder, £35 for key and £35 to program transponder to car by a dealer early last year. Tried a number of key/transponder specialists who said things like "the Saab type fobs can only be programmed once so a new one is required each time" and "we don't have the special software" so I continued to risk just having the one key.
Well my local Saab dealer has just supplied (£25+vat) and programmed (£26+vat) a new one albeit with a Saab badge rather than a Cadillac badge, otherwise exact same thing, and they told me the old one was also reprogrammed along with the new one. They can be reprogrammed infinately and to any vehicle (up to 5 per vehicle) as long as one works already. And they don't have to be new SAAB transponders, even the rectangular ones can be used, although another dealer might say otherwise if he ain't supplying it.
yeah the thing with those saab (and bls) remotes is that if you loose them all you have to get a new theft module as well as new keys
in order to program a key you have to daisy chain it from another key that's programmed already
and the modules come with a chip that acts as the first key, then they program your keys copying that chip's code