By stiffening the engine in the bay the power created goes directly to the ground instead of being absorbed by the stock rubber monnts. This puts the power to the ground and more efficiently. It also helps handling by holding the motor in place while taking corners.  Stiffer motor mounts will also prevent wheel hop during take-offs.  The mount which I made is the front motor mount which is a common one for breaking. 

A member of the Chrysler3LiterV6 club makes some for about $65 but I made my own instead for financial reasons...  ha.  If you upgrade one motor mount than make sure you do the rest or you will quickly destroy the other ones.