Anyone tested the Drag caused by swapping exhaust?

[robones]

Notice how the Z's exhaust is designed, it's engineered so that the air passing underneath the car curves through the bends of the exhaust through the rear diffuser in a smooth way. This causes less drag at high speed.

By changing the exhaust to a two piece set up, i.e: Fast Intentions, Berk, etc. you are are creating essentially a parachute on the rear of the car. I would think drag is significantly increased by this design.

When you remove the CAN design, the rear bumper gets exposed and creates a huge gap which traps air underneath the car just as its exiting through the rear.

The better designs would be exhausts similar to the stock setup and/or the nismo setup. Stillen, Greddy have similar designs which leave less of a gap in the rear bumper.

Your thoughts?