A drop in doesn't require a tune for this, its just a filter inside the stock box.
Honestly if you feel like you have the need to go for it, but honestly your just spending the money for a filter that looks pretty but no benefits from it, I threw one in mine just to say I did and could say what it did.
Nothing happen, if you wanna spend the money, go get yourself a CAI like that Shane said.
But also think a CAI or Short Ram, Plus a tune or an AP gets pricy, so if your on a budget or don't want to spend around 600-1,000 for an AP and Intake then go with a stock filter and save the money from a filter that looks pretty outside your airbox that no one will see
2011 WRX Premium