Are getting headers worth it at all for $500. If so what will they do? Are they worth it? Any negatives. Basically i wanna know what they will do.

 

headers are a waste of money IMO..they push the tq and hp gains further up your rpm band for top end use at the sacrifice of low end spooling and change of boxer exhaust note.
The USDM STis have a low red line compared to its JDM counterparts,so use that power band early to spool and see what your turbo can do, than limiting it

The stock headers are fine. Rigoli uses them on many of thier cars because the cast iron is strong and holds the head in for exhaust velocity purposes

If you were to get headers for the 2.5L turbo, look into the JDM twin scroll header setup.
a great resource to see what the setup can do is at http://www.type-25.com/
its a special edition that is available in the UK by Litchfield

 

always depends on what it's used for. I don't go to the strips or anything and probably won't be for a while, so i'd rather just keep my stock 05 headers as well as my low end power. besides, don't think i want the change in my exhaust sound while just driving down the street.