This is designed for racing. A stock C4 does not need the frame stiffened.
However with that being said, there is currently about an inch of flex when you lift the car without the top being installed.
1998 Pacecar Original Owner Stock
1993 Callaway Ruby Red ZR-1 #219
1991 Callaway Aerobody ZR-1 #1026 Purple Pearl Mist
1991 Shinoda Aerobody ZR-1 #1696 (Under Construction)
2003 50th Anniversary Roadster Pacecar
1990 LPE ZR-1
ZR-1 Registry Member #1393
NCM Lifetime Member #2551
Pacecar Registry Member
Grand Sport Registry Lifetime Member