I purchased a c4 from TCI years ago and installed and had problems right from the start would not engage in reverse until it was reved up to 3000 rpm's and then the car would shutter and shake as it tried to move , forward gear would not work at all , pulled out and they paid shipping they went through it and sent back and was worse , pulled out sent back they sent me another trans. and that one was even worse than the other one contacted them they said to pull out and send back they would go through this one and send back to me with them paying the shipping , i had had enough and told the guy i had better things to do than keep pulling their trans out because they would not work and if i had to pull out and send back they were going to have to pay got my labor of constantly pulling trans ,which seemed reasonable to me at the time for my efforts . he stated they could not do that and they issued me a complete refund of the trans . I have not had any more dealings with them and i could not recommend them from my experience . I just think they should have better quality control and check their trans better before they ship out.