Sounds more like a rear end problem. Sometmes, when the differential's clutches are worn out- the car will feel as though its twisting when in reality it is slipping on one side.
Pull it up on jacks, in neutral, and attempt to turn the rear wheels forward and backward. If you can get a wheel to turn forward or backward (a quarter to half turn or so) loosely before the diferential engages- there's your probem.
I had a C3 that did that. It would slip under intial acceleration and deceleration.
car designer's biggest pita = people...people want to have lots of elbow room, ez get in and out, don't like structural members penetrating their body...plus its gotta be fast(light weight)...soooo, it ends up with a powerful engine in a steel cage with minimal elements all in the least obtrusive, and unfortunately least functional, places.
of course these problems apply to all designs, and every design group must decide how much rigidity is required...EVERY car flexes to some degree.
Grab a rear wheel and pull it side to side like you are 'steering' it. if it moves ANY amount, you have worn bushings and/or wheel bearings. The car should accelerate straight and true on level ground when you tromp on the gas-wheelspin notwithstanding. Antother clue is if it tramlines on rutted/uneven roads. The car should feel steady and stable, if not I suggest MOOG suspension products.