Wat's the difference between these? And also wats the best brand?

 

The underdrive pulley goes on crank shaft and help to reduce the amount of power that the accesorys draw, like the AC, PS and alternator. The only real application for an overdrive is if you have a heavy drawing electrical system and then you would put one on the alternator.

 

What is the best underdrive pulley for a 98 neon dohc. I heard it was unorthodox but i want to make sure.

 

As far as I know they are really all about the same. Its just a brand preference.

 

so how exactly does the underdrive pulley create a lower amount of mechanical resistance without adversly affecting those systems? is it just a smaller pulley than stock?

 

Basically, yes. Companies that sell them will also claim they are lighter and better balanced. If they really are or not is a matter for debate. Personally, I can think of better ways to add a few horsepower, but it's YOUR car!!!! Enjoy!