Yes you can drive the car with a open DP
The flanges are turbo to DP, DP to Mid Pipe, Mid Pipe to Y pipe, Y pipe to mufflers. If I remember right.
174,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. Also CHECK YOUR OIL, these cars use it.