Yes for "definetley worth it". No for "its cool, but dont need to have it"

-Needswings CAI: YES!!
-Flowmaster Muffler: Yes!
-R1 Concept front drilled & slotted rotors: Yes
-R1 Concept rear drilled & slotted rotors: No
-Magnecore Wires with NGK Plugs: Yeah....(thats a 50/50)
-Zex Nitrous system and purge kit: No
-H&R springs: Yes
-TVT Rear Camber arms: Usefull if lowering the car, otherwise, nahhh

Hope I could help