I wouldn't ditch the rear sway, adds stability to>
..and strength to the whole rear end. RoyW should be the guy to ask, but how about going with a stock rear sway and an adjustable front (like ST or Dinan) set on medium/stiff? That should dial out some of the rear bias. Have you been up and down the matrix of tire pressures/temps? That would be an easy way to tune things. Get an accurate tire temp and pressure gage so you can build a spreadsheet. Not sure exactly where you are located, but remeber that HP parking lot me met in for Kimball's (corner of 495 and RT119)? That building is totally abandoned now. You could set up a couple cones way in the back, and no one would ever know you were there.
Bob88 ///M5, RIP