Also it is funny some people say the 9" is the best thing out there then there are people who say the 8.8 is just as strong. This is going to be a built 9" not in stock form. Just like the C6 some people love it some people hate it. Is it personal preference ?
The Ford 9" can be made very strong delivering a lighter weight axle having higher ground clearance and good on-road manners. Currie states that the 9" would be better for high speed off-road and jumping, such as seen in Desert Racing. Keep in mind that Jopes
is correct regarding strength issues in factory form, but this depends upon your application.
Regarding the VSS, I have a 1990 with a mechanical speedometer which only requires the differential VSS for RABS, which I eliminated. I did consider the Brea Auto Electric Transfer Case Yoke Mounted Speed Sensor, but after consulting with them I could not be assured that the signal works with RABS.
On a side note, I did consider a High Pinion Third Member but Currie claims a 20% loss in gearset strength due to the reverse rotation design, as they are intended for front axle use. Not that people do not use them in the rear, just with a significant loss of gearset strength. To reinforce this point, Currie recommends that only tires up 35" be used when installing a High Pinion in the rear.
I have concluded that a 9" rear end would fulfill my needs and that I could make a 9" nearly as strong as a D60 or 14 Bolt. The personal question is cost vs need. Admittedly, my needs have been met, but at a cost. At the same time, I have been having fun with this build and I think this Currie 9" may be stronger than I will ever require. With the Nodular Case, V-Welded Tubes and Full Back Brace, there should be minimal deflection. And the 9+ Race Third Member components should be as strong as you can get, not to mention the Performance 35 Spline Axles which are 1541 Alloy, 1.5" diameter, 400% stronger than stock and rated up to 1200 HP.
BTW, my driveshaft fit just fine. The Currie has 1350 Yoke so I used a Hybrid 1350/1330 U-Joint to complete the connection. See the Currie F9+
link in my signature.