Help setting up Speedtech torque arm for more traction

[joeelutz]

I realize that most everything chassis related is a compromise and us in the PT crowd would like to have our our cake and eat it too as far as handling and straight line acceleration goes. I realize this may be a ridiculous question. That being said, I have to ask. How detrimental to handling is running a drag radial in the rear with a fairly short sidewall such as would be used on an 18" wheel? Has anyone tried autocrossing such a tire?