Am I gunna feel any power gains with this. I hear it's the poor mans supercharger. Also my car is auto/tep so that makes it seem even more pointless. Although it's a cheap mod for how much power you get off the line it just seems worth it. Any opinions?

 

Not familiar with putting gears in a bmw, but I'm sure it would help. What ratio is in it now?

 

Whatever your % increase in gearing is will manifest itself into the corresponding increase of torque at the back wheels.