We have the Signature Class Warranty on both our MB's. It's like your Starmark. The E300 already had it on it when we bought it.
It was an excellent deal compared to any aftermarket warranty. We paid $1575 for the 3 year full warranty on the C230, and it covers most everything on the car (same as factory bumper-to-bumper) for the first two years or until 120,000 kilometers. Then it's a major component warranty that covers lots of stuff until three years or 160,000 kilometers. The warranty period kicks in at the end of the factory warranty.
There's no deductible and the process is identical to getting "regular" warranty work, which is easy.
It also included the "uprated" road-side assistance package, complimetary loaner cars, and some other goodies like trip insurance and so on.
We haven't used the warranty yet (touching wood) on the C230, but just had our first visit on the E300. An odd repair, the thermostat failed, and Helen had no heat. Not expensive, but a few things here and there and the warranty cost is easily saved.
As to your tranny, you might remember my friend Kevin having the EXACT same problem with his C280/722.6.
The dealer did NOT repair the transmission. They ordered a NEW one, and swapped them out. Shortly before his appointment, the tranny failed completely. It made some awful noise, and went into limp-home mode. He cleared the limp-home by turning the car on-off, and then drove right to the dealer. They had a new transmission air-freighted in, and swapped it in.
They kept his car for a few days to make sure everything was fine. It drives like a dream now, and he's hoping things are fixed for good.
He's also considering the Signature Warranty, after signing the $5500 warranty bill for his car...
...guess MB lost money on both you guys!
1998 C230 "Black Betty"