If you do your CPL in US in a Jar school, it will be through the UK system, and will need to do some sort of conversion for your IAA licence, it may be only paper work, not sure. Did you already do your ATPL's, if so that determines what country you do your CPL in.
I have already done my ATPLs in the UK and am working towards a British licence.
The Instrument Rating (or any other rating)part of the training does not require that I do the training in the same jurisdiction as licence issue. So, I can have a British Licence with an Irish instrument rating.
Thanks for your post, but I don't need any info regarding licence conversion or anything like that, I would just like some feedback from former MEIR students regarding their experiences and advice about the course.