There are no "Certified Installers" for the standard IMSB Retrofit, there are only "Preferred Installers". Preferred Installers are just those who have carried out the jobs that are willing to pay to advertise their services.
The "Certified Installers" are for the IMS Solution. These are only SEVEN installers across North America (5 in the US) that have been invited to the positions after attending both my classes. These Certified Installers must pass a rigorous evaluation and their practices are constantly scrutinized by Charles and I. Two weeks ago we revoked a certification from a shop that made one mistake by exercising poor judgment by retrofitting an engine that had experienced IMSB failure.
Here's the IMS Solution Certified Installer list:
Certified Installers | The IMS Solution
So, a preferred installer has no certification, its nothing more than a shop that has carried out an IMSB Retrofit and wishes to advertise that.
If it were my prerogative ALL shops that carry out the IMSB Retrofits would have to pass an evaluation to get any sort of advertisement or endorsement. But, thats why I am the Developer, not the seller.