i got my car back from the shop a few weeks ago and i had one of the complete headlamp unit replaced on the right side. i noticed last night that the new unit is a hell of a lot brighter than the other side. i think it's cuz it's brand new which means that the older one is probably dirty inside so it's not as bright. any other explanations? also how can i clean the inside of the old projector if thats what it is?

 

I really doubt it's dirty since the inside of your lens should be sealed most of it's life unless you have a leak somewhere. Most likely, though, the reason is that the plastic turns old. When they turn old they just get more and more cloudy. You really can't do anything about it.

What you could check is the bulb. Did they put in a new bulb also? If they did then you can swap the bulbs left and right and minimize the effect since bulbs also grow dimmer as they grow old.

 

I have the same problem and my car is a 99. My car got a new headlamp in January. If your outter lense is cloudy, you can use some plastic polish on it. It help. On my car the brightness is not much different, but when I am facing a wall the new lamp has a razor sharp cutoff compared to the old one which is fuzzy.