I'm using 25mm spacers with bolt at the rear, supposed to be from Japan. Not sure whether it comes with cone.
Pros: Wheels really flush with the rear fender. In terms of handling benefits, can't tell cuz bigger ARBs were installed on the same day. Balancing is not really an issue since it's at the back.
Cons: Since I'm still on aged stock shocks and spring, with heavy load at the back (2 passengers and stuff in the boot) the fenders will touch the tires (actually just right tire) while going over mild uneven roads. Rarely if going over very uneven surface at speed (eg highway near Putrajaya Sentral), sagat will also occur even with no load at the back. Not an issue if you're on adjustables or if you don't fetch buffaloes at the back.