This link helped me understand more about it. Be sure to read the FAQ's on the bottom of the page. Makes sense after you read it a few times.
<< Quoting the link above: >>
Q. Is the modification emissions legal for emission controlled vehicles?
A. In the United States, this modification is not legal on it's own. It is possible that steps 3 through 5 may be 49 state legal with the use of certain types of fuel injection that are already certified for 49 state use. Please contact the fuel injection system manufacturer or your local state regulatory agency for this information. It may also be legal in some states when replacing an engine in an older vehicle (without the BBD system) with an engine from a year with a BBD system. I have no specific information on what is or is not legal in any particular state or with any particular system(s) and I will not be able to answer any questions or give any advice relating to legality. Remember that you are altering the emissions control equipment and in many US states this is illegal.
If you live or operate the vehicle in a country other than the United States, the legality of this modification will depend entirely upon the laws of your country. You will need to contant the relevant government agency in your country for this information.
Q. My state has no visual inspection. Will my Jeep pass the smog test (sniffer test ) with the modification?
A. First, I can't really tell you that, among other things it will depend on the condition of the rest of your engine and how well it is tuned. I can tell you that in my Jeep with this modification that I have passed a sniffer test with results as good as a new 4.0L fuel injected Jeep engine and I have also failed the test miserably, depending on the the condition of the engine and its state of tune. In general, some people who have a BBD system that is malfunctioning or who have idle difficulties may find the modification to be of some benefit because it may help reduce misfires at idle. Each misfire sends a puff of unburned hydrocarbons out the exhaust and lessens your chances of passing the test. Your results will absolutely vary and we make no claims of any kind regarding the impact of this modification on any emmisions testing in any country.