You only think it moves backwards but it's just an effect when your car is moving. Do you mind if I know where can I purchase BBS wheels?

It's difficult to install the Greddy all by yourself. You got to bring your car to the nearest auto shop.

If you want to prevent damage, you have to remove the alternator before you weld car parts. That's what I also did when I lowering springs in my 1996 Corolla.