I sold my single piston set up and went with the KH set up. If the 4 piston isn't a good set up why are they making them new now? SSBC has them. Wildwood has them.
My 2 ton rollback is dual piston calipers on all 4 wheels. Why? They are superior to single piston calipers.
They have also decently came back to use on upper priced cars such are the SRT-8.
