Proposed Dept of Transportation & EPA regs...Link
Page 35 extract
(5) Certified motor vehicles and motor vehicle engines and their emission control devices must remain intheir certified configuration even if they are used solely for competition or if they become nonroadvehicles or engines; anyone modifying a certified motor vehicle or motor vehicle engine for any reason issubject to the tampering and defeat device prohibitions of paragraph (a)(3) of this section and 42 U.S.C.7522(a)(3).
Page 35 extract
(5) Certified motor vehicles and motor vehicle engines and their emission control devices must remain intheir certified configuration even if they are used solely for competition or if they become nonroadvehicles or engines; anyone modifying a certified motor vehicle or motor vehicle engine for any reason issubject to the tampering and defeat device prohibitions of paragraph (a)(3) of this section and 42 U.S.C.7522(a)(3).