To be safe yes, and also to get the most from the exhaust system you should. So I'll just say yes, you do.
it's the thing sticking out of the exhaust with a wire attached to it...if it doesn't have one and it's causing problems then you probably have an aftermarket exhaust and you need to weld a bung on the exhaust to attach one
Depends on you goals and your budget, if you are looking for just a little boost in power aftermarket exhaust, a tune and steeper rearend gears (numerically higher) will give you a noticeable difference in power
yes
jardine pipes
Yes, legally and for the computer to function correctly you will need a catalytic converter.
It is an aftermarket exhaust that is more free flowing so it increases horsepower and changes the tone of the car
NO you can get one aftermarket.
Headers are aftermarket replacements for the exhaust maniflods. They are the parts bolted directly to the heads on the sides of the engine. They channel the exhaust from each cylinder down to the exhaust pipes. :)
Two-brothers is a brand of aftermarket exhaust systems, mufflers, and more. An exhaust system is tubing used to guide reaction exhaust gases away from a controlled combustion inside an engine.
engine tune just a major service then maybe a new exhaust system
Only if you have a lead foot.
It shouldn't unless you messed up the 02 sensors.