You can use Kimbrow spurs, just remove the 2 1/4" shims from the diff by the red spacer and you may need to reshim the axle for center. Using the 1/8" diff balls will move the diff side tire out 2 shims worth.
Frank watched me plow into outside wall in the front chicane at IIC. After I bounced what felt like 30' backwards, I drove off. Slapmaster part number #105 - black foam bumper, 4 grams. Wasn't a moment of grace, but I did finish my race. I did shear the e-clip off inside the shock. There was just no way it was going to stay in place with that kind of rapid deceleration. Moral to the story: run a foam bumper! A few bucks for a bumper is way less then a chassis, body damage, and wasting your time in the pits putting a new chassis under the car.
Think I'm going to ring some door bells for candy.