Character equipment

Equipment like new probes or new clothes aren't necessary in any way, because they don't do anything yet(New probes do not give you more money, so they aren't neccesary!).

Cameras

The cameras aren't important yet, because the developers are still working on a function for them.

Laptop

The Laptop isn't something you need, because there is no gps in the game.

Protection

The protection is good to buy, because the Hail Cage will protect your car 100% from hail.
The Collision protection will take away 20% of damage of the collisions.

Tornado Warning Antenna

Is good but isn't that necessary I would buy it, because you don't need to always look on the map, until a tornado appears. But that's a personal decision.
There will be a small pop up in the left corner saying : A new tornado warning appeared on the map

Wind Speed Measurements

Good to have, if you are in a foggy location and you see that your windspeed jumps from 30km/h to 120km/h or more..... maybe it's too late but atleast you can see it ;D

Everything else

Everything else that isn't mentioned above, is just cosmetic. That's always personal preference.

Maybe it's always personal preference, but this was only to show the use of these "items".
I hope this helped. Now enjoy playing and never stop chasing ;D