Cusco Nissan SIivia S15Further to Corey's previous post, Cusco provide some great further information regarding the benefits of the Tower Bar, also known as the Strut Brace. This great reference explains the benefits from a professional driver and amateur drive's point of view.

A great video is provided which really illustrates the benefits of the tower brace in keeping the two suspension towers braced to provide more predictable and stable cornering. At less than $200 and one of the simples parts to install, it really should be near the top of your modification list.

See the two links below for further information:

Cusco Tower Brace information in original Japanese
Cusco Tower Brace information translated via Google