Ways to compare what weapons/gadgets I am missing?

[Jordan_Peterson]

Hey,
I am a completionist of some sort and wondering how could I compare what weapons, gadgets, upgrades, rare items, I am missing and which one I already have.
There is nothing on the map left to do, so I am also wondering how do I know I got all cars possible to buy or obtain in a legal way? (Not talking about that extra car from the race quests-line).
Is it just a "look for yourself" of how would you guys approach that?

[Rabidnid]

Make lots of money and buy 26 cars. its around 1.25 million last time I checked.

[Jordan_Peterson]

Originally posted by Rabidnid:

Make lots of money and buy 26 cars. its around 1.25 million last time I checked.

my point is, how do I know I already have all of them, when I bought every icon on the map already! Some cars are hidden or only obtainable through quests.
Same goes with unique weapons or other interesting stuff.

[Rabidnid]

The Autojock achievement is the the 26 cars, not any of the free or quest related cars.

There really is no way to know if you have all the weapons and clothes without using U tube guides.