This depends on how much performance you want out of your car and how much you are ready to pay for it. Without any doubt, cold air intake improves the performance far more than a short ram air intake. But they are expensive and also harder to install. This means that if you are getting professional help to install the air intake, the cold air intake will cost you more on labour charges as well. A short ram, even though it will improve the performance, you won’t see a huge spike. They are also louder than a cold air intake. But much cheaper and easier to install.