Piper Girl,
Im not too sure about this but I believe you might have a problem with an american issued JAA CPL as its really issued in England. I would check with the IAA just to make sure its recognised and you wont have to retest. Im not too sure about this but I would double check just in case. I wanted to do my ATP's through bristol and was told as its an english JAA licence the IAA may have a problem with it eventhough its JAA too.
I would however suggest you save up the cash and then do the ME/IR as opposed to doing it part time. It will stop you from getting rusty and as we all know at 400euros an hr we wouldnt want to be getting a little rusty.........