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I have the front and rear upper strut bars. Do I need lower tie bars and sway bars too. Will I need both (tie and sway for the front and back) or one or the other?

 
Rep Power: 419

You don't NEED anything. It's actually better if you have no sway bars at all and shocks and springs that change their stiffness while cornering. Awesome!!! That doesn't exist for our cars though, so it's best to get sway bars to make the car more flat in the corners.

You should get a tie bar in the rear if you get a rear sway bar upgrade. You don't need a tie bar in the front though IMO. I don't have one and there hasn't been any problems. I've run my car so hard that I cracked a rim though, so that says something for the way I drive.

 
Rep Power: 403

get all the bars you can, a good damper system like tein flex, x-brace, and some forged rims... you will be set to take corners like nobodies bussiness

 
Rep Power: 416

you'll see the biggest difference with a spring/shock upgrade then any bars.. then its sway bars then strut bars