The front strut tower brace is a bar that connects the two strut towers together and decreases roll in turns.  The front end feels significantly more planted to the ground both in light to moderate and aggressive turning situations.  BT

The purpose is to keep the tops of the struts identically spaced with each
other so that the front camber does not change. (Camber is the measurement
of the angle caused by the tipping in or out of the tops of the wheels WRT
the bottoms.) Some cars come with a factory link between the struts. My
folks' new Lincoln Continental does.

These camber changes typically occur when the suspension compresses;
especially when it compresses more on one side than the other as in
cornering. Some cars suffer more than others. My experience is with the
95+ Maxima, and I can testify that the STB makes a very significant
difference.

-Steve Cutchen

Pictures to come.

Next possibilities to come:  

JWT ECU 

thicker rear sway bar 

cold air intake