Very big weight difference with a complete tubular K-member with a rack and coil overs would be the magor gain. I went with AJE for a light weight drag car. HDK would be the prefered dual purpose due to strength. My street Demon will be all factory suspension. Remember the stiffer the bars the more push you'll have in turns. You need to transfer weight to the outside on entry and exit . The weaker the bar the looser the car will be.