Do Steeda UPD's void warrentys? Somebody told me they don't. Are they worth the $200?
If they aren't worth it I'm just gonna save for some 3:73"s instead.

 

How do these things actually boost horsepower?

 

UDP's... Under Drive Pulleys.

I'm almost positive they don't void the warranty and, yes, I believe they're worth it for the extra RWHP they help free up. My problem with them is if a person does a lot of stop and go and extensive idling AND is running a high electrical load it may pull more from the battery than I'd be comfortable with. I also heard of overheating issues but that would only be a problem with extensive idling IMO.

The 3.73's would be a nice mod. Certainly would feel quicker but will have a minor negative impact on you gas mileage.

IMO, do BOTH!

 

UDP's don't increase crank HP. They free up some of the wasted mechanical/rotational inertia to the wheels. Similar to the aluminum drive shaft and it's weight reduction reducing rotational mass and freeing up some ponies.

 

I did the UDPs and the aluminum one-piece driveshaft at the same time. It made a huge difference in the butt-dyno! The engine could rev up faster when going throught the gears.

Note: I have the optional 3.55s so I figured that the UDPs would not affect me in the charging or cooling departments since the factory pulleys where designed for the car with the stock 3.31s.

 

they only go for $200... why not. they provide proven horsepower for not much $$$

 

they work on a weight issue and on a perisitic drag loss. there is less drag on the front of the motor allowing it to spin up faster. Saves gas too! One of the first things i did to mine. its gaurenteed free hp and saves gas i would totally do it and it will probably pay for itself in gas i a year or two

 

is a 1000 watt kenwood amp bumping 2 10s too much electrical load??

 

Learn it yourself. I'm done.

 

i would say you would be fine as long as you have a 1 farad capaciter for your amp. if you dont have one get one! it will really help your subs thump and once you got the cap i wouldnt see why the udps would hurt your charging too much. supposivley they only effict it really minimally and i run my shaker 500 full tilt with all my lights on and heated seats ect ect and havent seen any issues.