The bulbs that they come with are probably just ultra-cheap made-in-china bulbs that have a dark, dark blue paint or coating on there, making them produce WAY less than legal output, and the overall construction is probably horrible. I would not suggest using those bulbs.
The Sylvania Silverstars also have a blue coating that reduces light output, but they are much better in terms of construction and should have legal output, even if they only last a few months to a year to achieve it.
You might also have to re-aim the new headlamps to get a decent beam, but if nothing helps, even with the Silverstar bulbs in there, they are likely just cheap lamps with a poorly designed reflector and you're finding out why cheaply made "black diamond clear" headlights are a bad idea.
There are some aftermarket manufacturers that have decent quality lights (Depo, TYC, etc.), but there are a LOT of others that just produce them for show use, and they aren't very functional (or legal) in terms of being used on the road for driving.