Hey, vbenz, welcome to the forum.
I can't speak to invoice pricing but if you post in the 204 forum you'll likely find more information, lots of folks have them and can give you a ballpark of what you can expect to pay, which often means more than the invoice anyway.
Re: norcal dealers, I'm not sure if you really mean "Northern California" or whether you mean "bay area" since those are technically different, though often used interchangeably.
(When you have a minute use the user cp link to update your profile re: your location.) In the bay area my relatively limited experience is that they're all about the same and there is variance even within a dealer (some people have great experiences, some decidedly less-so). Pretty much what you're finding, none really stands out.
Parts-dept wise (nothing you really have to worry about buying new, but it sometimes is reflective of a broader attitude) the guys at SF Benz are great. Autobahn's service department is clean and well-organized, although their service writers are hot and cold and there seems to be a higher-than-normal turnover. (SF Benz is an older shop, still well-organized, when there I saw a service writer changing a headlight bulb for a 209 owner, that seemed like a great customer service attitude as opposed to making her wait for a "tech" to come up, and no, she didn't have the appearance of someone you'd typically expect to be doted on by men.) SF Benz is not as easy to get to (depending of course on where you live) so that might be a determining factor.
Smythe I've never been to, but have heard some bad tales about, but never anything glowing. When I was looking for a local source for the cluster tools I called them and they said "$29 plus $9 special order charge and $5 shipping" (these are $15 items if I recall correctly) and that was enough for me to cross them off the list of someone with whom I'd willingly transact business, but if you're in the south bay or further south, that's really the only option.
I'd probably shop around a bit, maybe hang out in the service depts a bit and ask some of the folks in there who are waiting what they think, would they repeat their experience, etc.
Good luck, happy shopping, and enjoy the ride,