Question about steering wheel shaking while driving

[Doublemyv]

Hi Guys, I have BDR RT4 build # 1946 that came to me new in Dec. 2019. The car has a Coyote motor, Tremec TKO 500, and had stock suspension. I live in SoCal, and the roads are not great. The steering wheel shake was noticeable from day 1. After checking with Reg and the crew @ Boynton Beach, they advised that some steering wheel / cowl shake was normal. I spent a lot of time on wheel balance, steering system inspection, and tightened up all the bolts that hold the angle iron braces from the frame up to the windshield mounting under the dash. No real improvement. The steering wheel shake / cowl shake is noticeable to a more or less degree on every drive. Smooth roads, no shake. Rough/patched blacktop roads = lots of shake. I now have over 4,000 miles on the car, and have just put on a new set of Nitto NT555G2 tires ( 18" ) in the 295 rear width, and 245 front width with Road Force Balancing instead of standard wheel balance. I also just added the Eibach front springs that Jay recommended to soften up the front of the car , and it definitely rides better over rough roads, but the car still has steering wheel / cowl shake. I mention the cowl shake because during my relentless attempt to minimize the shaking, it became obvious that BDR has a MINIMALLY supported dash structure with small angle iron bolted on vertical supports from the frame tops to the dash support piece. The small supports, 6mm support bolts, and the weight of the windshield frame & glass led me to the conclusion that BDR engineered the car to have the dash supported by the strength of the fiberglass, with some steel as a supporting role. So, I keep everything tight, move my hands from the 10 & 2 positions on the wheel to the 5 & 7 positions on the wheel ( to reduce my hand/arm shaking ) and I drive the car with a smile despite the shaking. Wow, long explanation for shaking, but it is annoying, and can't be simply fixed. Mark