The underdrive pulley is also lightweight. Being that they are cut out of billet aluminum they are significantly lighter than the OEM steel pulley.

It's technically a Lightweight Standard Sized Crank Pulley vs. a Lightweight Underdrive Sized Crank Pulley

ohhhh ok, so they both go in the same spot, their the same thing just for different purposes. therefore you have to get one or the other correct?

Yes.. one or the other.

The standard pulley uses the stock sized belt.. the underdrive pulley uses a slightly smaller belt (because the pulley itself is smaller, and requires a belt that's shorter)

As it's been discussed, the standard sized is for supercharged applications, as underdriving the supercharger would spin it slower and reduce the horsepower gain

^ so this would be ok for a s/c, I just want to make sure cus I plan on buying the stillen s/c

If you're planning on the STILLEN supercharger, you would need to use the Standard Pulley during that time. We have a lot of guys running the underdrive until the supercharger is available, and they will swap then.

^So it's going to be a twin screw s/c ;)

It will be pulley driven.. ;)

i feel kind of worried about underdriving all the belt driven componenets. will it affect the steering considering it will be underdriving the power steering pump?

I've only heard 1 person out of the hundreds that have purchased mentioned the steering at a dead stop seemed to take a little more effort, but that feeling was gone after a couple of days (getting used to it)..

Most others report no change is felt at all.

Very nice! 5whp gain (mind you, on a hotter weather too) from crank pulley is pretty decent!

Yeah I haven't felt any hugely noticeable change. I've had no issues with my steering or anything else since putting the UD pulley in.

does this underdrive pulley cause the headlights to be more dim than before considering its underdriving the alternator?

No. My voltage meter hasn't dipped below 14 either, which is where it was prior to the installation. I don't think there will be any adverse effects until and unless you install some monster stereo system or something.

will this have any affect on the power braking system? or does that system run off the battery, and not engine?

Okay, look, there are no negative effects to anything, period. None. Zero. Nada. Clear?