Cobra front spring on a GT?

I've just finished an IRS swap on my 2002 Mustang GT and I want to add some H&R race springs. Do I get the Cobra kit (since I need the rear spring for the IRS)? Will the front cobra springs from the H&R race kit will fit on my GT? I have 275 front tires like the cobra and a vortech supercharger to make up for the weight diff!

Thank you,

BTW, The IRS with a full tilt boogie racing delrin bushing kit feels unbelievable! its like a new car!