pullies don't make power, they free it up. The peak measured at the wheels for both will show a minor increase, but the underdrive will show a bit more. The biggest gain is in how the engine responds ..... rips up quicker.

 

so underdrive it is!

Any my power steering and alternator shouldnt be affected much if any

 

You should be fine with it. You have about the same car as me as well as almost the same climate.