No. Section 27151 VC prohibits the modification of the exhaust system to amplify or increase the noise emitted by the vehicle, making the vehicle not in compliance with Section 27150 VC or exceeding the noise limits established in Sections 27201-27206 VC. Section 27151 VC does not prohibit all modifications to an exhaust system. It also does not prohibit all modifications that increase the noise level of the exhaust system over that of the original, factory-installed exhaust system (as it did until 1980). It only prohibits modifications that result in a noise level higher than those specified in Sections 27201-27206 VC. Accurately determining compliance with Sections 27201-27206 VC for enforcement purposes is generally impractical. Enforcement personnel must make an informed professional evaluation to determine if excessive noise statutes are being violated.