I've done a lot of research and looking through these forums but I'm yet to feel comfortable buying one of these from unorthodox. I understand that it does give you more HP. How much exactly? I'm also powering two amps (600w & 1000w) amp, and 2 1000w 12" subs. If i'm listening to music on idle, is it going to kill the car? One last question, are the new belt sizes hard to find or are they avaiable at any auto parts stores? Asking a lot because this car is my daily drive and I would love to keep it reliable.

I run a UDP and my headlights don't dim at night. Don't know about your amps. Not sure of the HP gain but it is worth it. So is a bored out TB. The manufacturer can tell you the right belt sizes and they are common and available at any auto parts store. Just do it, lol.

Haha ok. Do you notice a big difference in the way the car drives as far as low end torque? I know for a fast I lost some low end with the headers I installed.

i have an AF/X udp and i barely notice any difference, but it will help in the long run if you're planning to stay all-motor.

Yeah planning on stay all motor. I would love to go turbo but I don't have that kind of money to be throwing around. Couldn't imagine the headache of being pulled over here with a turbo in California.

You will be fine. I ran two amps - one for the speakers and one for the sub.

NEVER had an issue with charging or dimming headlights.

You shouldn't lose any torque with this mod, it should actually help you in all RPM ranges. You don't really "get" more horse power, but it frees up horse power due to reducing the rotating mass on the crank. I think it is a great mod. I especially noticed a lot of difference in the higher RPM ranges.
As mentioned by another poster above, most manufacturers will have a list of part numbers for easily accessable belts. I know my Bomez UDP game with a list of PN's for Gates Belts (Napa).
The difference in weight from the UDP crank pulley and the stock crank pulley is huge. Its hard to believe that the factory wouldn't have used an aluminum pulley to save on the rotating mass--it didn't even have to be undersized (underdriven)--that would have been sweet.
Now after I installed my UDP, I did get some minor headlight dimming at idle when the bass hit hard, because the Alt is being underdriven. You can fix that by purchasing a smaller diameter Alt pulley. Also, I noticed that at about 1000-1100 RPM's, charging is back to normal.
Many people run a second battery in the trunk along with capacitors to help with this issue on BIG stereo systems.

95 Avenger 2.0 - Hahn 16g, DMS 8 injector setup, UDP, Big FMIC, HKS SSQV, MSD Coil & Wires,
ZEX Nitrous System, QTP Cut Out, Mandrel 2.5" Exhaust with cat delete, MP 60mm TB...and tons of Carbon Fiber

Great info. Thanks guys!