What really doomed the car was the fact that Cadillac buyers, when they buy a convertible, they just want to push a button and watch the top disappear…The Allante had a manual top and it was a tricky 4-step process to lower or raise the top…Great care had to be taken or the top fabric would get pinched in the steel top-frame and damage-cut the material…On the bright side, the '87-'89 models all came with an aluminum hard-top which many owners left permanently installed. However, the hardtops became an option in 1990, a $3500 extra…The cars are all virtually identical, except for the last year, 1993…These Allantes introduced the then new Northstar overhead cam V8 which gave the car 100 more horsepower which made them very lively indeed. The front seats which were 6-way power leather Recaro seats but in '93 these were replaced with the standard Eldo seats which most people found much more comfortable…Today the Northstar powered '93 models still bring a good price but the pushrod cars can be had for little money…
To me Toyoto products seem to be designed in a straightforward manor & are relatively easy to work on.
Actually, I thought of “luxury car for a mechanic” as a car, in the luxury segment, renowned for its mechanical correctness or superior mechanical design. For that, I think a properly-restored, rust-free vintage M-B diesel would fit the bill nicely. A rolling Rolex, on a road full of digital watches.
@Mustangman, what did the Germans ever do to you? ;)
Geez, as a person with German heritage via way of the PA Dutch, I wish you wouldn’t serve up softballs like that! 
For a second there, I thought [Ford] Mustangman might conceivably be [P51] Mustangman, leading to an interesting exchange, to say the least! (Alas, not to be…suppose I should put the popcorn away now…)
My German side wouldn’t have any issues, my Danish and English sides might… No French anywhere in my lineage… 
Wie Bischt, meanjoe! My lineage is also Pa Dutch/Pa German/Pennsilfaanisch Deitsch. My paternal grandparents were Lutheran from Lehigh County; spoke “Dutch”.
Anyway, I put a junkyard trans in a mid 2000’s Camry a while back. Easy job. Most mechanics I know seem to like working on Toyotas.
I agree with Docnick here . . . get the Lincoln, it will be easy(er) to work on for the DIYer and cheaper parts-wise. There are a lot of them out there, lots in salvage yards, lot so folks who can give you advice. Don’t go German, English, Italian, Swedish, or anything but American or Asian, you’ll be happier. Good luck! Rocketman
As a minimum, look at access to the oil filter, belt(s), and spark plugs. Then thermostat, alternator, and starter. If you’re thinking of checking valves, look at ease of valve cover removal.
What are the prerequisites for a luxury car these days? While I enjoy the convenience of remote controlled outside mirrors, the mirrors that can be programmed for different drivers is a bit outrageous in my opinion.
I worked on a 1930’s Rolls Royce once and it appeared that the R-R reputation was based on reliability that was accomplished with redundancy and over building/under stressing all the critical components. Today bells and whistles seem to be the distinguishing characteristics.
I typically shy away from luxury cars. The main reason is all those creature comfort items tend to break and get expensive to replace as the car ages. I keep a car until the wheels fall off, and nuisance failures just irritate me. A basic car that is easy to work on is always what I look for.
I agree with B.K.'s post above…That’s why, along with the Allante I keep a Crown Vic for most driving…The Allante is a toy, a hobby car. It’s a challenge to see how long I can keep it on the road…Yes indeed, one by one the gizmos and gadgets crap out and you fix them, live without them or bypass their function.