What is the purpose of a strut bar?

 

it's for strutting

 

Provide additional rigidity between strut towers. In theory, they reduce body flex during hard turns. In reality, they are a pretty show piece made to bling up your engine bay.

 

Most people do it for looks. Good brake compound and fluid goes a long way. Unless you go to a road course and track your car, you don't need bigger brakes. bigger, slotted, crossdrilled rotors don't really affect your braking in daily driving. Your panic stop distance is almost the same.

 

In addition, when the engine bay gets hot, the strut bars will expand, thus giving your car more positive camber, which is a bad thing. It does improve chassis rigidity though.

 

So basically it has more negative effects than positive effects?

 

Hard to say, up to ever individual to see if the benefits outweigh the negatives. I threw them on because theoretically they may prevent long term flexing and misalignment of the chassis, but I definitely wouldn't expect them to improve handling in the short run.

 

Oh okay. Thanks for all the info!

 

They basically have no effect for a daily driven car except aesthetic appearance.

 

When a 5AT G is put into drive, is the rear drop down noticeable? If so how much? I'm getting coils installed soon and if the rear drop down is noticeable, I would want to set my coils so that when parked, the rear is almost unnoticeably higher, and when in drive, I have a level stance. Thanks

 

Huh?

 

I've heard that when a 5AT is shifted into drive, the rear end of the car lowers

 

Someone was screwing with you.

 

Thanks

 

This is correct. It is called squat (or anti-squat when it goes the other way)

here is one description
http://www.how-to-build-hotrods.com/tuning-4-link.html

In the stock g35, I believe the movement is minimal if there is any at all. But if you lower the car, you move the roll center, and it can become significant enough to be a problem.

The thing is, if you see when you are parked in drive, it is even worse when you are accelerating with normal driving. To fix this properly, you need roll center adjusters. Or really really stiff springs.