you can go with any spring set up really. its just how miuch of a drop you want. Sportlines will give you a 2.00Inch drop. Pro kit will give you a 1.5 and H&R's SS Springs will give you a 1.75 in the front and 1.5 in the rear.
By the way this is the wrong section to post this question but its alright. but next time you will want to post in the Modular Mustang Area and then go by the year mustang you have. Since you put this in the wrong section that is why noone responded to you.
you can use whatever springs you want. you just need to adjust the tire sidewall height whenn you buy new tires. mines lowered 1.5 up front and 1.75 out back. I run 18's with a 35 profile and have nooooooo problems.