I need to find out what Grade and Type of Aluminum is used in AUS B4 bonnets?  I'm thinking of modifying the factory intercooler intake openning so I can get more airflow by moving / lifting the factory openning higher and further foward.  I got the idea from the current WRX but would prefer something not that aggressive.

I was thinking about cutting out the sheetmetal around the stock scoop so I could move it then use my english wheel to roll up the infill panels, tig it and the infill in place.  And I also plan to use the 35mm APS intercooler insert to help with further airflow.

The other question I have is, what WRX's have an aluminum bonnet? Current model? I ask because I'm looking to find 2 vents that I can add to the bonnet to get some heat out from under the bonnet like to older style WRX.  Worst case I can make something myself but you can't match a factory look.

Cheers Kenny