Can't answer many of your questions, but if you want a remote for this car, the dealer is the only place to get one programmed. I wouldn't chance one from eBay or somewhere. Although earlier models seem to work fine, from '98 on, it's a dealer only item. I would try what you have thought about the sunroof and go from there...post back as you find out more. The way the key works in the door of an '01 seems to be determined by programming as well, so to the dealer it is for that too, I believe.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.