Originally Posted by
1300gt
It will not give your engine more power. Only lower reciprocating weight / rejuice point of inertia.
I would spend the money elsewhere. You should be careful what you buy off "ebay". 
Incorrect. If they pulleys are a smaller diameter as the original poster states he suspects, then (also as mentioned) they will under drive ancillaries thus freeing up more power at the flywheel.