Dont know why you say "Since I need new springs in the rear...".
Personally, I would get the Eibach "street" spring (I had these). THey are 10% stiffer than stock (450-580# fronts and 250# rears). THey lower the car like 1 to 1-1/2" and look and feel great (not harsh).
The CC plates will be helpful in getting the front end aligned correctly after all four springs installed.
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Darius Rudis
Roadracer: Home built t-arm/panhard suspension powered by an S-trimmed motor :-)
My Mustang Page