Go here and educate yourself on what's available.
zerothread/207927
SVT is right. I have heard nothing but positive things about Grounding Gear for AT's.
You already have an intake... so you'll want an exhaust as well.
You have a sweet car... don't go cheap on your parts. Most here buy from everythingg35.com.
STI's are fast for sure... but they belong in the mud!