V6 is a 2 piece as well but it is not the same as the v8 one. The v8 one is indestructibly stronger. GT has a speed limiter of 147 mph. I tested this....in Mexico. Aerodynamic limits on the s197 are about 160-ish.
2014 Premium GT, SGM, Brembo, Auto, Tech, Comfort, etc. GT500s, Steeda UCA, VMP auto tune, 100 shot on BBR tune, best et: 11.38 at 120.85
2012 GT, Candy Red, Brembo, 3.73, Tech, Comfort, etc. Procal tune, Roush upper, UMI LCAs, Steeda red bracket, GT500s, 28X10X16 Hoosier slicks, best et: 11.91 at 115.23 RIP
One of the first Mods I did to my car was replace the driveshaft with a one piece - What did I gain besides a significant reduction in weight which gives a better rotational mass - just piece of mind I guess and maybe just maybe 1/10 in the 1/4 mile.