Hey guys! I bought a 2001 is300 2 months ago and now that i have done the wheels it is time to start adding more power. I am going to do a cat-back and header on it and was wondering wich header i should go with and how much power they add? I was thinking of going with and obx header but i wondered if they made as much power as the hi end ones. Also i want to do a cat back and was wondering wich sounds the best without being rediculously loud . Thanks