Start with headers you'll get the most power out of those by far.. Excluding the S/C..
You have 3 options Comptech, Stone Headers and OBX.. You're going to get about 25-30 hp.. After the headers you'll want a intake, either a Comptech Ice Box or AEM..
Comptech - Pricey but extremely high quality
Stone - Basically in between the Comptech and OBX
OBX - Have had some failures on cars but Cheap