The top a-arms bolt directly on, be sure to use your end caps from your stock a-arms because they fit a little loose without them. I do have the spacer kit mentioned in the thread. It cost me $100 shipped, including longer tie rods. I think its only $50 bucks if you dont need tie rods. The pictures are in that thread of the spacers installed. You do have to modify the lower a-arms, requires a little cutting not too bad. It is definetly worth it. I spend about $500 bucks for a full front end setup, Including the 450 a-arms, spacers, tie rods, and shocks. I run works tripple rate 400EX shocks with my 450 a-arms because they are longer.