Jay Halsey didn't base the X1 off of the K3. He compared his project cars to what was on the market and tried to improve in the areas he felt the car would need to be better. There was emphasis on making his car better than the K3 because that was the king of the 1/8th scale world at the time.
wyd - OFNA is working on cheaper chassis and bodies for the X-1. I'm not sure the reason for the excessive cost but I know it has to do with shipping and where the parts come from.
Jim - Amen!