I just spent several days replacing all of the sounds for the TC2000 mod, making small physics changes (altered the suspension geometry) and reskinning the cars (70% done). I've now got a race car that can do anything from stage rally, rallycross, street circuits, permanent road courses, dirt ovals, paved short ovals, intermediate speedways and superspeedways. Take that Gen 7 cars, I'd like to see you guys take on a rallycross circuit.
I also resolved the porpoising issues entirely. Apparently adding bump stops was the solution. If your springs are so compressed that the car is bottoming out, adding a few cm of rubber bump stops will keep the car from continuing to bottom out at high speed.
Other suspension changes helped improve how the car holds up to jumps and curbs. They won't handle a trophy truck track (trust me, I tried) but they will survive a few dozen laps around a rallycross circuit without breaking.
All 6 brands have distinct engine sounds too, along with all the right 80s era Group B and IMSA turbo noises. I love the different noises old race cars made and really wanted to incorporate that. Also, when a swarm of them start letting off the gas and downshifting for a corner it sounds like a gunfight from all the backfires.
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"Many of us like to ask ourselves, What would I do if I was alive during slavery? Or the Jim Crow South? Or apartheid? What would I do if my country was committing genocide?' The answer is, you're doing it. Right now." —Former U.S. Airman (Air Force) Aaron Bushnell