Taking out the baffle will allow the bike to move more air through the system which will improve top end horsepower but will affect back pressure which will lessen low end torque. In any case the carburetor will need to be rejetted to compensate for the increased air flow to keep from leaning out the engine.
It will make it sound better and it will give you more power. For an example I made this one hill once but i didnt make it easy when i took my baffle out of my dirt bike I count fly up it and it sounds cool but try not to get mud of dirt in the exhaust after market pipes suck sometimes you have to jet your carborater and you waste more gas.
metal - duhhh.....
A slip on exhaust will give a dirt bike more power. A full exhaust setup will give you even more power than a slip on.
yes
It could be condensation from hot exhaust gases on the cool exhaust pipe.
Opens and closes the intake and exhaust valves.
no
Put a potatoe in the exhaust pipe
that's an opinion , but i'd have to say pro circuit
yes you can but don't put it near the exhaust pipe.
plug up your muffler next time
it smokes out the exhaust...