Lowering an ITR 1.5" is too much lowered, if you don't mind my saying so. The car will not handle better at that height.

The only thing I'd really recommend with a clear conscience is Spoon springs, which are not expensive and are designed to work with OEM shocks or something like Bilsteins. This will lower the car a little bit while also making an improvement in the handling because the springs are a higher lbs/force rating.

Since Spoon springs are progressive, however, the ride is not that harsh.

Don't just lower an ITR to get a look...know what you're trying to do.