decreasing turning radius is easy, just grind about 1/8" off each side of the steering stops at the bottom of the steering stem until you find the sweetspot.
i just checked it out... this machine is about maxed out as far as countersteer options.Yes, I have had a Sonic for a while now and love it. Not the push I am trying to fix now, just making the turning radius itself shorter.
I just went and looked and it won't be as easy as it seems. I didn't know what those goofy looking things on the back of the bottom a-arms were for until now. They appear to be a "rim slider" the way that they are positioned. With the stops at the stem where they are there isn't much clearance between the rim and the "rim slider" on the a-arms. I am afraid the geometery is what it is.