If these cars need to be red-lined on a weekly basis, then they were a poor choice for this application, as most of the buyers of the DeVilles and Eldorados that they were used in, were in their 60s and 70s; to say the least, these aren't the most aggressive drivers on the road.
Basically. It was a feeble attempt at trying to lure a younger buyer and/or MBZ/BMW customers. The problem they somehow failed to realize, that seemingly everyone else saw but them, was that most Deville drivers or people that are looking to buy one, are older, more relaxed drivers, while people who are looking for a MBZ/BMW probably, unfortunately or fortunately, depending on side of the fence, didn't even consider a Deville.
Original poster -- quick update:
The car now has 133000 miles. I've had the following service done (aside from regular oil changes):
* New battery. 80 bucks.
* Full transmission service -- drop the pan, replaced fluid, filter and gasket. Cost: $179.00. Effect on performance: noticeable and positive.
* Full radiator/cooling/heating system service and flush. Included new thermostat and radiator cap. Also tablets. Cost $200.00.
I learned a very important thing with this job. GM requires DEXCOOL for this aluminum engine. GM indicates that DEXCOOL has a service life of 5 years. THIS IS FALSE!! DEXCOOL is only "good" for 3 years. While it might theoretically provide the required specified "protection" for your engine, after three years DEXCOOL begins to turn into an ACID and eat away at your seals and everything else in the engine. My mechanic actually had a couple of seals in his desk that were victims of expired highly acidic DEXCOOL. They were gone -- half eaten away. I've noticed no problems with the temps on this car or with overheating, and I live in a very warm area -- daily triple digits throughout the summer months.
Replaced a leaking brake line -- front driver's side. Cost $179.00. This was probably a legacy issue that came with the car. It was the original factory brake line. The car had over 125,000 miles, so meh. Bleep happens.
I also have a freon leak in the AC system. Recharges cost 100.00. I had it recharged once. Three months later the tank was dry.
Other than that, no other problems. Fit and finish are holding up great. Paint job and leather are both about a 7.5 on a 10 point scale -- same as when I bought it. Engine performance, shocks, brakes, electrical systems all work great. Car is still very solid. I continue to be impressed at the build quality of this hog. I've always only owned large American cars, so I'm familiar with creeping development of creaks and squeaks that come with a larger frame, body roll, greater surface area and weight (no physicist here -- just guessing). But this car seems to resist all that so far.
The engine is still a beast as well. I know I should get it tuned up, but performance-wise there's just no reason. It's quiet and smooth, and blows away most everything on the road. If I'm on the highway doing 60, and for some reason I need to get to 85 or 90 like that, this car can do it, no problem. It's like a locomotive -- it seems to excel cruising at higher speeds. Given the weight and the front wheel drive, it's impossible to knock it around or off the road. Does well with bad road conditions as well. In the snow, this car can smoothly power up the same steep slippery inclines that rear wheel drive Town Cars and Crown Vics from the cops to cab drivers slide down after getting halfway up -- without even having to use traction control.
People that are used to being crammed into tiny, thin skinned, Mexican or Japanese made Pez dispensers notice quite a difference riding in this thing. Like being in a battleship. A favorite game to play is "guess the speed" where people think we're just going 60 or 65, but we're really at 87. You can't tell the difference. Too bad they just don't make 'em like this anymore. And they never will again.