Englishal - I'd like to meet your friend who did an FAA IR over a weekend. He must have had some very recent flying, logged or not. It can't be done otherwise; the workload on the checkride is too high to just jump in from any sort of "normal flying".
He did the FAA IR in literally 5-6 days and about 8 hours. BUT but but ......initially he did the IMCr in the USA and all previous logged instructional time was with FAA CFII which may have been an advantage. He also had JAA CPL and had just done the JAA FI rating. He'd also used the IMCr for a number of years before getting the FAA IR....
He then converted to JAR and now flies Airbuses (A300 I believe....maybe he'll be along in a bit
)....