Drive Shaft Shop Manual 3'' Aluminum 1-piece Driveshaft - 2013-2020 BRZ/FR-S/86

Super easy install (jack the car up, un-bolt the 2 14 mm carrier bearing bolts, un-bolt the 4 14 mm pinion bolts, slide the old driveshaft out, slide the new one into the transmission, bolt the pinion bolts back in place and your done), great results. No more axle-hop when I launch hard, no more carrier bearing bouncing around and the car feels more alive now. My car breaks loose shifting into third now and even triggers traction control shifting into fourth (engine has only an intake upgrade, otherwise stock). It does make a hollow bell-tone noise at certain speeds but it's not offensive and in my opinion, sounds cool. It's not super loud but you can hear it with the windows down. I only have 1 issue with this mod: the stock pinion bolts are not quite long enough to give you more than 3/4 of the thread into the nut due to the new driveshaft's thicker mounting plate. Forums have lots of answers but I just ordered some 32 mm long (stock are 30 mm) m10 bolts in 1.5 thread pitch with matching nuts. Got them in Titanium too. These are big bolts so the stock steel ones are heavy. By subbing in Titanium I shed almost 2 more lbs, bringing my aluminum driveshaft Install down to the same weight as the carbon shaft (with the stock steel bolts) for way less cash.
Anyways, if you're on the fence about this Mod, take the plunge. It's worth every penny.

There is a noticeable difference is acceleration with this mod. Definitely reduction in the drivetrain slop as well.  I did this in conjunction with the Perrin trans mount and torque solutions shift bushing. Much tighter feel. Cabin noise did increase slightly as you can hear the trans more now. I don’t think the shaft is really noticeable IMO. Would do it again in a heartbeat!!!