Ill give you some pros and cons...
Easy 10-15rwhp with simple bolt on
Zero harm to engine or components
Better exhaust tone
Will not pass emissions
Illegal due to removal of primary catalytic converters (Even if you move them to after the headers it is still illegal federally, and in many states. They are only allowed to be replaced in the stock locations)
Exhaust smell (some dont care)
OBD II cars will require o2 simulators to not throw error codes
If I hadn't have already purchased a set of MMW headers I would be down for this.