Both are good. ISO is not necessary but it does act as a layer of insulation to stop heat from being conducted from the engine block into the runners and plenum. How much good does it do? I can't really say.
If you like the sound and look of the exhaust, get it. Those are the most important factors. Unless you plan to go FI in the future. Then you might wanna look into 3" systems.
If you like the sound and look of the exhaust, get it. Those are the most important factors. Unless you plan to go FI in the future. Then you might wanna look into 3" systems.
