"emission compliant" tuning is just another disclaimer some companies are starting to use. Same as 'off-road racing use only'. Emission certification requires running the FTP75, HWFEC, US06 and SC03(AC2) test cycles and all the results must be within regulation limits. One must also test the worst case vehicle configuration (weight, tires, axle, drag, etc). There are two methods the EPA offers here. 1. Reasonable basis testing conducted at an EPA approved emission lab showing all tests are in the box. 2. Obtain CARB EO, this process is long, expensive and it seems CARB is still learning how to handle each vehicle application.