Josh, build your brackets with a large range of vertical adjustment so you can play with it. As you lower the PHB the car will push more and more and you`ll have to compensate with rear spring rate and roll bar rate. It doesn`t take long for that to get really uncomfortable in the street. Run soft bushings in the upper arms in at least one end to allow some deflection so that the PHB can dominate the RC and you don`t have 2 conflicting roll centers fighting to control the car. Keeping the bar closer to the original RC will also reduce possible conflict and make your brackets shorter and more rigid. There will be a lot more load on them than you might think. Triangulate them well and add a crossmember between the rails just above it to keep them from spreading under load. Mark SC&C