Originally Posted by Sonic Mustang
Well, there goes logic.
A heavier car will require stiffer springs to obtain the same levels of performance as a lighter car. That's why convertibles have different spring rates. IT DOES MAKE A DIFFERENCE.
The OP should take a look at H&R springs. They are very high quality and available in different rates and ride heights. I'm running Super Sports on my Mach 1 which may be a little too low for a real daily driver, but H&R makes springs that leave the vehicle at original ride height and others that drop it about 3/4".
Also to tack on. I am not sure if the OP was asking about the "minus cobras" but the cobras have IRS and it would not fit.