im thinking about buying one if there any good, what exactly does it do
and will one off ebay be ok?

 

there supposed to spin the air and mix the air up a bit more for better atomization of the fuel.Same theroy of the tornado deal...Personally i wouldent put one on my car if they were free. If you were going to get one e-bay is fine there all the same...

 

this is gonna sound dumb, but does it go inbetween the tb and the intake manifold?

 

yep