Thanks for the input.

One thing your realtor may request. Instead of the notes, just swap
out the modified smoke detector with the correct one so nothing has to
be declared. It'll make the sale go easier. You really don't want to
mess it up. It's not like your mod will be the deal clencher that
makes the buyer choose your home. It very well could be the thing that
makes the buyer walk away.

Think about it, if you were buying a house from, say, Steve Wozniak (a
known good electrical guy, think Apple computer) and he said, 'by the
way, I modified the smoke detector so it would...' Would you trust
the life and safety of your family with it or would you want it swapped
out?

Also, considering all the horror stories there are about the 'buyer
from hell' (I know someone personally that had such a buyer, what a
major hassle it was and it cost lots in legal fees but that is another
story. Their buyer just wanted to back out after the time frame but it
still cost the seller legal fees just to clear up the mess.) do you
really want that in the mix?

Let's say your buyer gets your notes, is a dream buyer, all is well,
and then 3 months later the house burns or something like that. Now
you have given them written descriptions of what you did. Who do you
think the law/insurance is going to come after? What if they aren't
such a dream buyer and they modify your mod and it burns. Now what?
Now their insurance company and your insurance company have you on the
stand and you say, 'I just added *this* relay, I didn't do *that* to
it!". I just don't see the gain here.