[Nonfractal]

My approach is to spend on cars, tools and controllers.
A pit box is always bottom of the list so a DIY tool caddy meets my needs.
I see some pit boxes that are nothing short of full engineering workstations. 
That approach is fine if you race BSCRA and need EVERYTHING with you, but I don't. 
It is also fine if you have plenty of pit table space at the club or event but often, space is tight. 

So, DIY tool caddy from which I take one tray of "must have" tools, drivers etc.
The caddy normally sits under the table, out of the way and not taking up real estate of the pit table.

I keep the cars separately from the tools in a modified Carrera 1/24 case. 
I have 3 of these cases, one for each of the 3 clubs I race at,  so while the tools remain the same, the cars are separate and distinct. I never race cars tuned for one track at another track.
It's also important for me to slide the car boxes under my bed. Space is valuable. Regular pit boxes just don't go.

Also, the modified carrera boxes are a good advertisement for visitors, journalists etc. All cars on view. 
Two hands, two cases. It makes sense to me. 
AlanW