I hear 'ya. I've had many of the same deliberations about daily-driver deliberations. The fact I drive 100 miles/day plays a big role in the equation, a tow rig was never an option.
Auto-x events are a minimum of 50 minutes each way for me, with most being a little further...but still within my 100-mile AAA covered tow range. My M42 E30 spins at about 4k rpm at highway speeds. My tires are a bit shorter than they should be, so that should improve a little once I put the right sized rubber on there. The M42 just doesn't feel as relaxed or smooth as the straight-6. I routinely did 6+hour drives in my last E30. even with 4.10 LSD it was like butter at 75mph.
I took my son to sit in an FR-S/BRZ/86. He was 7 or so at the time...so too small to sit in the front seat. The rear seat access was difficult, at best. He also couldn't see out the rear side window. The rear seat also looked pretty uncomfortable. Overall, not a good choice for riding with the kiddo in the back so we checked it off the list, and worse than my daily driver Civic Si (EP3) at the time. Now that he's big enough for the front seat, it would make a lot more sense. Noise can also be a factor for kids liking/not liking cars. Mine thinks the E30 is too noisy...and it's running a cat and resonator.
We test drove a new V6 mustang and FoST in the process of finding my current car. The mustang drove great, but the gas mileage was pretty bad for a V6 and the seating position killed my back. It was plenty fast and made better sounds than the 4cyl turbo version. The FoST was just underwhelming. Maybe the higher level package with better seats would have sold me on it. I also drove an FiST on an auto-x course when they launched...this was great, but didn't have enough room for road-trip duty.
I ultimately bought a VW Alltrack wagon. 30mpg for my commute, can easily fit two mountain bikes or surfboards in the back, and simple roof rack integration. It's also a manual, which is pretty rare. GolfR suspension and APR tuning are common mods. I suppose it's nice to know it's an option if I'm not able to have my "fun" car.
I'd be concerned about the expense of maintaining and repairng a modern car that's tracked regularly. Especially in the event of a catastrophic failure.
As far as other options go...I've spent some time in an Rx8 on an auto-x course. I'd have bought one if it weren't for the fuel mileage and reliability reputation. I still might eventually get one if I ever part with my E30.
Cadillac reliability scares me. CTS-V and ATS may be good...but there are at least a few threads on GRM about all the failure points in modern Cadillacs.
I'd consider adding 128i/135i...but repairs can be pricey.
There are plenty of known failure points in different subarus. I was impressed with the stock suspension in the blob-eye STIs.
I think an E36 BMW is a good compromise if you're doing longer drives and may have kids in the car. They're a bit more modern and comfortable...they're also very cheap. THe E36M3 and E46M3 have got to be at the bottom of their depreciation curves.
I had a similar attitude about RWD only for a track car until I went for a ride-along run in a modded 400hp GTI. Thing was ridiculously fast. I wouldn't rule-out FWD all together.