So i want to get a pair of lowering springs but looking at American Muscle what is the difference between the

Eibach Pro-Springs set
Steeda Sport Springs
Steeda Competition Springs
Ford C-Springs.

These are not for me but for my boyfriends birthday which is in April. He has a 96GT.

 

Without knowing much more, I'd go with the Pro Kit. They are a good basic lowering spring.

If you happen to know what kind of shocks and struts he had, it would help.