The Jag XJRs are what started me down this road long ago, when I noted you can pick up an early 2000s one for $5k in nice shape. That spiraled into this. She doesn't really care for Jags except the F type too.
I thought about the other sizes of AMGs, and keep thinking that if I have to deal with an auto, I want to go big or go home, literally. The c class isn't really any bigger than the Mazda, and the E class just seems to be missing that little bit of extra presence and whatnot that a top of the line S class has, which will hopefully make the auto seem OK. I'd like whatever it is to have more back seat room than the Mazda for trips with more than just the 2 of us, or when we bring more than the Z4M can handle.
If they made an M7, I'd be all over it. The e38, though very nice, isn't in the same league as these two for speed. The e60 M5 is getting to be basically the same price as the e39, except the manuals. It also is a little too far into the digital age for what I want as a DIY person. The others were designed in the late 90s and hav been pretty well figured out.
The SHO would probably do the job fine too, but the others won't really depreciate any more while this will. Also, no manual and under 400hp.
We aren't looking to be competitive in one lap, just to run it and have fun while doing as well as we reasonably can. If we wanted to win a class I'd be looking at building up a mini R56 for the vintage looking class.
The M5 would no doubt be better for One Lap but I think the S55 would be better for everything else I want it to do. Both have fine tire and brake selection to get through the event too.
Thanks for the feedback so far, glad to see I haven't totally lost my mind.
Edit: the Mazda. No build thread, but I should make one. It basically evolved as we needed to replace stuff, except for the drivetrain. It is all bolt on and in, but I haven't seen another one with similar mods anywhere.