Direct bolt ins are NOT legal if they exceed the OE rated volume spec, which 99% of them do.
Section 375. Equipment.
Subsection 31. Mufflers and exhaust systems. Prevention of noise.
Every motor vehicle, operated or driven upon the highways of the state, shall at all times be equipped with an adequate muffler and exhaust system in constant operation and properly maintained to prevent any excessive or unusual noise and no such muffler or exhaust system shall be equipped with a cut-out, bypass, or similar device.No person shall modify the muffler or exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor or exhaust system of such vehicle above that emitted by the muffler or exhaust system originally installed on the vehicle and such original muffler and exhaust system shall comply with all the requirements of this section.
A muffler is a device consisting of a series of chambers or baffle plates, or other mechanical design for the purpose of receiving exhaust gas from an internal combustion engine, and effective in reducing noise.
An exhaust system is a series of mechanical devices for the purpose of receiving exhaust gas from an internal combustion engine and expelling it into the atmosphere.