Unfortunately the only way that you can test this SLD is by seeing if the car shuts down at 180km/h.
Here is a small video of my test run...
Looks like my speedometer is getting the signal from the ECU.. The speedometer stops at 180km/h, but the revs keep climbing. My Circuit Timer registered a top speed 197km/h. (not necessary top speed for the car, but that is best that I could do with the traffic conditions..
I thought the Daisan Keihin would be a good test road, even though it is usually crawling with police.. but, at high speed, Daisan Keihin was a bit on the curvy side... not to mention a bit crowded..
anyhow, enjoy the video..