What are you guys running with.

 

It all depends on how loose you want the rear to be. The thicker the looser it gets. Also take into account if you plan on doing the front aswell.

 

Think it also depends on hollow/solid and adjustable vs not and front vs rear? I have a 19 mm non adjustable neuspeed rear and22 mm non adjustable neuspeed rear and, seems like the car turnsin more readily and the *** end is a little looser, makes for more controlled, spirited driving and ebtter roadfeel imo, though I havent had much time to play with it yet.