Be that as it may, my car has been on track since about 2004 so take that for what it's worth. Miata is likely similarly flimsy but is smaller, lighter, and runs smaller tires so doesn't see the loads that our cars do. I haven't missed any races due to the crack in my trans tunnel. Wheel bearings can also be driven around. My argument against the newer stuff is it's a lot more expensive. The issues you bring up are, IMO, minor and mitigatable. For about $1200 you can have nuke proof 4th gen front hubs, much cheaper than a newer platform. Even then I just keep spares in the trailer and only lose 1 every other season or so. I personally haven't seen any cracked k members. Trans tunnel cracks can be welded, Mustang torque boxes are allowed to be reinforced. What's left?