I guess this would be considered a 'noobish' question. Anyway, I have just recently started keeping track of my museum cards, is there anyway to see which ones I have just received [i.e. daily sign in bonus] without going through the entire manufacturer comparing the numbers to the list on mygranturismo.net?
The answer is no. However there are any strategies that will save you a lot of time. I will explain 2 methods that can be used together:
First Method: Compare new countings vs old countings
What I did was to print a copy of the list and crossed out the ones that I had. Then each day on the first screen you can see the total number of your cards for each manufacturer. For example if you had 34 of the "Fords" and the next day you have 36 you have 2 new ones. If you have 2 or 3 of the same card it only count ! in the list. I'm down to needing only 5 cards. When I got down to about 40 cards needed I made a list of the ones I needed so I could check my other accounts if they had them.
Yeah, that's what I've been doing. Except instead of printing out a list, I've been using mygranturismo.net. I was just hoping there was an easier way

Because it's not fun going through Ford or Citroen.
This is possible because the the number for each manufacturer only shows how many different cards you have and not the total number owned. This way doubles wont count for your total.
How it works: As said above you just need to compare your mygranturismo.net number to your in game number after receiving cards.
I am assuming that you don't want to keep track of those that you already have but received another one (because it wont make sense, even for trading purposes). If you receive cards as a gift you don't need to apply this because the number and manufacturer are displayed in the gift menu (before receiving)
When you detect a difference between your granturismo.net and your in game count you should do as follows:
2. How to discover the missing card quiqkly
If you have less than 60/70% of the total cards of the manufacturer:
Cards are displayed in game in 4 rows. You should only pay attention to the last one (or the first if you want). In your mygranturismo.net account you look at your 4th card and compare the number. Then go down one line and compare that card with your 8th card on mygranturismo.net and so on. I you will save a lot of time. You could also do 2 or 3 lines in a row for big manufacturers. When you have found the difference your new card should be at that ln game line.
If you have more than 60/70% of the total cards of the manufacturer:
The first method will take you a lot of time. You should look at the cards you don't own on myranturismo.net and compare them to ingame listing. For example: you see the number of the first unowned card and will look in-game to see if you have it.
Aditional content:
Once you found a number of cards in a manufacturer equal to the difference between mygranturismo.net and in-game cards you should stop looking in that manufacturer. For example if you earn 1 card and found it is 6-ford you wont need to look further, just press O and pass to another manufacturer.
There is another techinc, but it isn,t very secure. I have noticed that the cards that you don't own and see for the first time take longer to appear in the screen. If you start go through your list and notice that in one line a card is taking more time to show is image, probably that card is a new one.
Hope it helped