Machined shock pistons for B6?

[andrewc]

The B6 has the updated shock shafts where the piston is secured via a screw in top of shaft...

Will any 12mm machined piston fit?
Or do they need to be specific to the screw in top system?

(thinking internal diameter of hole for shaft, obi all 12mm external diameters same!)

Any recommendations? Don't really want the AE 4 packs, rather buy in 2's