I had the same initial reaction with the T1-s. They were squirmy due to the deep tread in the beginning. After they wore down a little, I found higher tire pressures really help them shine, esp. with a front biased pressure (higher in front than rear by like 3 lbs or so). I usually keep them around 39-40 in the front and 36-37 in the rear, seems to work well for me. They are a step down from the stock sti tires however. Nothing short of an R-compound will satisfy someone used to the stock STi tires and the stiff sidewall. T1-s has pretty soft sidewalls in comparison, and from what I hear, the T1-r isn't all that much stiffer than the T1-s in the sidewall.
You might want to try an S0-3 next time....stiffer sidewall, less squirm from my experience.