Yep, where you will be caught out if it does not all match up is your first annual, or ARC. All mods, upgrades, must be accompanied by the relevant paperwork, and log book entries are a must. If you ever come to sell, or change regime, the omissions from logbook will be a show stopper.
I also think that engaging a fit out company, or an AP, or IA, would greatly assist. Always remember it is the paperwork that is the real gotcha.
