starts hard cold and has a stumble upon hard excleration.

Hello, my first "guess" is -- have you ensured the vehicle timing is proper after replacing the timing belt? Being off timing just a slight amount can cause this issue. My second thought would be -- sounds like a lot of parts being thrown at the vehicle without a proper diagnosis. You'd save so much by just getting a good evaluation of what's wrong with the vehicle instead of replacing parts. So many things could cause this problem, and only proper inspection and diagnosis can help. Good luck.