andrewc - you lucky chap! A pair of 430s indeed! We still have GPS150s and GNC250s.
Using a US IR in your N-registered aeroplane is a very sensible thing to do. But isn't it amazing how the aeroplane's registration makes soooooo much difference to IFR/IMC flying - if it has a 'G' painted on the side you can't use your IR, but if it has a 'N' then all is fine!