Where do you put daily recording of events(ala Franklin Covey)?

[Oogiem]

Let's suppose you are shopping for cars and you make notes (daily recording of events) for 5 cars a day for 3 days. Tuesday, Wednesday, Thursday. In the GTD system, where would you record that information?

I do it in 2 places. In my calendar I'd track how much time I spent shopping for cars because I use my calendar in a historical fashion for what I actually did as well as future plans. But the notes and stuff about what I saw would be in a folder for New car or car shopping or some other name so I can find all my notes in one place.