Rear Driveshaft - has anyone upgraded to 1 piece?

[LA_DRIVER]

Looking to put an aluminum 1-piece rear driveshaft in. You would think that it's the same as the G37 as the rear diffs and transmissions are the same but the part # is different for the FX35, FX50, and QX70. Although they look identical to me! Anyone have any experience with this? They should be interchangeable but I can't risk ordering the part without knowing for sure. Any help would be appreciated.

 

[LA_DRIVER]

Was just told that the difference in parts is the length which relates to the wheel base difference from our cars and the g37. 113.6" vs 112.2"

 

[LA_DRIVER]

~UPDATE~
I dropped off a OEM driveshaft at Inland Empire Driveline and they did the measurements: 64.5" long end to end. They are charging me $930 total w/ tax to build a custom 3.5" aluminum one-piece with dampening foam. This will be similar to ones Concept Z Performance sells for the g37/Q50. I'll report back once I install it.

 

[LA_DRIVER]

Installed the driveshaft yesterday, very easy and simple. It was a perfect fit. On the invoice they listed it at 65 3/8" not 65 1/2" so thought I would note that as it's a tight fit and there is no room for error in the measurements.

I haven't had a chance to drive it too much, but here are my takeaways: Sound and vibration is no different than OEM so it's super quiet and smooth. The throttle response has improved and it definitely feels like you get to the power quicker and it shifts smoother/faster. I also have Z1 rear diff bushings and a Quaife LSD. The combination of all 3 is a night and day difference in traction, acceleration, and grip compared to stock. Highly recommend.