Is there a disadvantage of using sway? I am thinking to buy a set of stillen or eibach, any experience? which is better?

 

To the extreme, stiffer swaybars will tend to make your axles behave like a solid axle. Too stiff, and the car will "skim" over bumps. You won't be able to put the power down and overall grip can suffer. This is the extreme case of way too stiff sway bars.

Swaybars are used to fine tune the car's behavior in a corner by redistributing the loads on the opposed axle's tires. So the question is: What are you trying to do with swaybars?

 

sway bar database: https://my350z.com/forum/brakes-and-suspension/119878-sway-bar-database.html

 

try reading that not really help to answer my question.I need to know will the sway bar change the way the car is design and will it cause any issue to suspenssion and tyres.Such as uneven wear, wear out faster and stuffs like that

 

Your car has a swaybar already. Anything you buy will simply be a replacement.

 

i have Stillen adjustables set to full stiff on an other wise stock suspension. i have noticed no abnormal wear issues with tires and used plenty of lube on the bushings when installing, no squeek isuues.

 

Not exactly true - they all offers stiffer settings than OEM so it's not exactly a "replacement".