Yes it does , where do you think that "extra" power comes from ? just drives things to a lower speed , it can be especially bad for things like your alternator as well, for the 10 or 15 hp i would look into other mods , ppl still do this one , cause its easy and cheap though
so its all up to you .... i personally dont have a UDP , since all the accessories in my engine are designed to spin at a certain speed , i really dont feel like underdriving them to gain more power to the wheels.
If you really want the 10 - 15 hp gain in your car , take out 100 - 150 lbs , its free to do that and lighter always wins, over brakes, engine etc
so its all up to you .... i personally dont have a UDP , since all the accessories in my engine are designed to spin at a certain speed , i really dont feel like underdriving them to gain more power to the wheels.
If you really want the 10 - 15 hp gain in your car , take out 100 - 150 lbs , its free to do that and lighter always wins, over brakes, engine etc