Regardless, they are illegal due to the increased noise that your exhaust system will be making. A straight pipe is just that, a pipe that is straight with no restrictions unlike most exhaust systems. There are a few reasons as the why this is illegal. The first being the obvious for noise ordinance.
Can you drive with straight pipe?
a race car style exhaust system is a bad upgrade for a street vehicle. A straight pipe, for example, can cause exhaust gas velocity to increase. This will likely reduce engine performance below 2,000 or 2,500 RPM, making your vehicle a little slower to launch from a stoplight.
Is driving without muffler legal?
You can drive a car or motorbike with no muffler as long as it doesn't exceed the maximum sound level allowed.
How much is a straight pipe cost?
A large part of the cost of the straight pipe is influenced by the city you live in, as well as the make and model of your vehicle. You should expect to spend between $1000 and $1500 on straight pipe installation for your car on average. It will take more money if you want to get the high-end titanium alloy exhausts.