I get that they wanted to make use of available vehicle parts, off the shelf tech and so on but I still shake my head over the Sgt York.
I can't get over the idea that they thought it was a good idea to base the system on a vehicle (the M48) that had been phased out of service and a vehicle that couldn't keep up with the tanks it was meant to protect.
Edit: If they were so intent on using a twin 40mm set-up, they probably would have been better off upgrading the M42 Duster to the latest tech and all-weather performance. At least the M42 had the speed to keep up with the M1.