On Wednesday, July 30, 2014 5:28:28 PM UTC-4, Steve Freeman wrote:
I have an SZD55 flying under an experimental/exhibition certificate in the US. It was manufactured at the factory in Poland. I have made some changes to the instrumentation in the panel and a few other items. Can anyone confirm that all that is required by the FAA is a logbook entry by myself stating what was done followed by my signature and pilot certificate number and then a statement by an IA explaining they supervised the work and their signature etc.

The work you describe may also require a revised weigh and balance in addition to the entry made by your IA.
UH