Police driveshaft

I picked up a police driveshaft off of a 2003 interceptor yesterday at Pull-A-Part. How do I know if it is aluminum or Metal Matrix Composite? It has the three color bands on it and stamped "POLICE". The bands are pink green pink. What is the driveline critical speed?

I also got the extended tailshaft housing from an earlier year CVPI with the easier to remove cross member.

2003 P71's have aluminum drive shafts. I think late 1999 and 2000 were MMC. Rear axle ratio plays a role in driveline critical speed. Aluminum should go up to 130 mph with 3.27 gears.

Thanks. So with 3.55s I will be safe and free of any harmonic vibration up to
130(3.27/3.55)= 119MPH?

Although I really never go above 95, and that's at the track for a brief few seconds.

Correct, if everything is working properly and your tires are good you'll be fine up to 119 at the track.

Thanks lights_sirens.

I got this driveshaft and the extended transmission tailshaft housing installed this weekend. I also installed new permanently lubed Brute Force u-joints. I definitely feel less vibration on the highway at 70+MPH. And this is with 2.73 gears still. I'm glad I did this before I swap in 3.55s.