I would agree on
lifed parts. Those must be changed (if mandatory), the change is in the maint records, and the traceability documents must be there also.
But most parts on a plane are not lifed. They are changed on condition. And one can never prove that it was "out of condition" at the time of the last inspection (even if it was completely obvious that it must have been so).
And the most important bits of maintenance which are a) inspection and b) lubrication are untraceable whether done or not. This is my biggest beef, based on 9 years of ownership, with maint companies.
Back to the registry move, I would not do it unless really necessary because it involves a lot of nosing around and if somebody is really diligent they could uncover stuff like avionics serial numbers not matching the records. Swapping avionics "off the books" is a widespread practice, which is obviously safe but the discovery would result in having to bin (or sell on US Ebay, for a pittance) the existing part and replace it with a part with paperwork. Obviously the avionics swap might have been done years ago, long before the current owner's ownership, but he will carry the can for it.
I did one transfer (G to N) which cost me about £5000 and on top of that were things like the ELT. I was grounded for about 8 weeks while various people were arguing about who should do what. It turned out that the plane had an extra GPS antenna installed; on a composite roof this is a massive can of worms but luckily it was in the factory-correct location. I had to drag the avionics blokedown to the plane (the now-defunct company was regularly doing stuff off the books or with dodgy paperwork despite being a CAA level 2 (?) design authorised company). He was well miffed to be involved in something he did 3 years previously, but I was lucky he was still around. In the vast majority of registry transfers the people responsible for any stuff that comes to light are long gone, or won't co-operate. It is thus a ripe area for ripping stuff out, or expensively recertifying it Loads of Garmin 430s have been installed by little avionics people, off the books or with a logbook entry when it was a major mod.
I heard of one case where the prop hub serial number did not match the records. The bill for that was the cost of a new prop. The old prop was almost worthless (well, an EASA 145 prop shop might be able to knock up a fresh EASA-1 form for it, after "overhauling" it, but that is rarely economical).
You get the idea, I am sure
