i noticed that cusco sells 4 different sway bars for the evo, however i noticed that 2 of them arent very thick. cusco says that one of the rear ones that they sell is 18mm thick, i thought that the stock rear sway bar in the evo was 22mm? why would you want to buy the 18mm cusco one when our car needs a thicker rear sway bar as it is? thanks for any help, i am very confused by seeing this

 

You should look at the chassis setup as a whole, not as single components.

If the car currently has stock suspension, going with a smaller bar might help in certain situations, especially in the rear. I am sure you have seen many photos from autocrosses or track events, where Evos lift the inside rear wheel 8-12" off the ground. If the objective is to put that wheel down to ground, one possible way to do that is to go with smaller rear bar

 

thanks for clearing that up!