Toys for my ass...
Having race harnesses without a roll cage is like signing your own fate. Seat belts are designed with a roll over in mind, one side is left open so the driver and passengers can duck to the inner side of the seat and be out of the caving in roof. However, with a race harness, you are kept in the upright position... Thus, your head is now the roll bar. So yeah, please keep stock seat belts unless you have a cage. 
By the way... Nice *** toys.

By the way... Nice *** toys.







