So what are the stock spring rates for the ITR? What length & rate are you using?
How much do they lower the car & do use any camber adjusters?

 

Stock spring rates are

Front 243 lb/in (linear rate spring) which is equivalent to approx. 4.34 kg/mm
Rear 243 lb/in (progressive rate spring)

They use a progressive rate spring to soften daily driving. Also ride height in the rear is slightly higher to give the rear a higher CG. When the cars are new sometimes the front will be higher than the rear - but I think this is due to the differences in the way the linear vs progressive rate springs settle over time.