Shum...
FAA 145 Repair Stations come in all shapes and sizes...from a small 1 or 2 person Specialized Services business all the way up to a large MRO employing 100's of people. I have about 30 years working in and around repair stations mainly in the rotorwing side...but they all follow the same rules.
Main difference I've seen between any FAA vs EASA operation is the fact that EASA is a fee driven authority and the FAA is a tax-payer/government driven authority. Bottom line being there is more flexibility and diversity in the FAA system.
Since this is a huge subject...I can answer more specific questions here or via PM...
w1