I have had my Shaftmasters 1 piece for four years now. No issues. It's been on two dynos over the years as well. The last dyno about two weeks ago churning out 726 HP and 655 TQ.
That's one helluva lot of hp / tq you have there ! Yikes... that's a bunch.
BTW... shaftmaster's rates their shaft at 750 hp. DSS rates their's at 900 hp. The DSS-DS is rated for 3450 ft lbs of TQ.
The CV joint at the axle end of the DSS-DS can easily be replaced.... for aprx $100.00 if it ever get's trashed.
Since I had the DSS-DS installed by my local Ford dealer, ( + BMR tunnel brace + DS safety loop, + the pair of steeda triangular sub frame connector's)..... I didn't want a potential gong show on my hands. IF I had to get the pinion angle re-tweaked a few times, etc, the $$ would start to add up.
Even then, the pinion angle should be tweaked at the dyno place across town.
The shaft masters is a good DS. But it seems to be hit and miss. Some folks have zero vibration problems with em..and other's ( esp automatics) are a real pita. 808 muscle has a 08 automatic with a M90 blower...and lives in Hawaii. His shaftmaster's DS was a real PITA. They couldn't get the vibration out of it no matter what they tried. 1-2 more replacement shafts sent out..same deal. He gave up in the end..and re-installed the oem 2 piece clunker.
I told him about my DSS-DS on my 2010 automatic. He ordered one, in it went... zero vibration problems.
Walker2T has the shaft master's on his 2010 GT automatic, (also with a M90). He had to get the pinion angle tweaked 3 times before they got the vibration out of it. Then he tells me a few months ago the DS vibrates at 120 mph. He had never had it up to 120 mph b4. So he left it for now...and just keeps the max speed < 120 mph.
Dunno what it is with the shaftmaster's + an automatic ( 5r55) ?
The DSS-DS shaft is the same DS for all 05-10 cars, and both 5 speed manual..and 5 speed automatic.
http://www.driveshaftshop.com/domes...-3-1-2o-aluminum-1330-has-no-clearance-issues