I vote for the rubber bushings as well. Street cars hit pot holes etc. I'd rather have the rubber bushings absorb some of that energy instead of transferring it to the K-frame. Many reports of bushings without sleeves letting the control arm move around. Then you get adjustable strut rods to crank the bushing back into a bind to keep things in place. I'm with the others. Sometimes better to leave the race track parts for the race track. With a sleeved bushing deburr and run it.