You can run 20s and Sportlines. See pic.
If you're wanting to make more room and get a softer ride, I'm intrigued by the BMR lowering drag springs. They have a soft rate for drag racing and they bring the car down for good looks, but they're not the normal stiff/short 'road racing' spring a lot of people seem to favor. Also, there was recently a sale on Vogtland springs where you could get the whole set, brand new for $70. But yes, the Ford P springs (same spring as the Eibach Pro Kit and the DUB edition) will raise your car back up some and have a softer spring rate. But the firm ride is still dictated by those Eibach shocks/struts. Every impact is going to be harsh with those no matter what springs you have.