Rear sway bar?
 

just wondering if anyone knows the size of the stock 2007 SI rear sway bar. i am thinking about getting the progress rear sway bar, which is 22mm. but i was wondering what the difference is in size. if stock is like 18-20mm i will say forget it, but if stock is like 15mm then myabe i'll get it. i am trying to find it now on honda's webstie but so far no luck.

has anyone here made the swap? any differnence? likes? dislikes? thanks