Nitrogen is used in filling aero tires and etc due to the lack of moisture if the nitrogen is properly processed and bottled. Nitrogen is mostly inert which is used as an anti-oxidant in everything from wine to fried chips to micro electronics to specimen sample preservation.
Moisture (water) expands when heated or contracts when cooled which alters that static pressure in a tire or similar closed container. Which is why aero folks and racer folks like using them in tires and dampers.
As for the twin dampers, the science of damping is complex and simply adding another damper (shock) is a guess at what the resulting damping might be. These days, many performance dampers have external reservoir to increase the heat capacity (controlled energy is converted to heat) and the dampers are pressurized to prevent foaming of the dampening fluid.
Basically, the idea of simply adding a damper might not achieve the desired result. What I will say, at the last LeMons race, Eye Sure Racing tried adding a second damper on their Miata racer.. It did not work out and made the chassis dynamics worst. They removed them soon after their first driver change. Keep in mind, this team has full use of a shock/damper dyno (Mazda USA) and they have a chassis engineer to work this out. They concluded the helper damper made the car perform worst.
In the off road racer world where dampers are pounded to bits, dual dampers when properly set up helps control heat generated by the bumps and lowers stress in the dampers.
Pro / WRC rally cars have serious damper technology, similar or identical to off road racers.. and many of them have dual dampers.
On a road car driven on mostly smooth roads, they are a bit over the top.
Bernice
I think Pete is on to something here. I remember in the Navy we used nitrogen to fill the tires of aircraft because it does not expand or contract under extreme heat or cold. This way the Plane can go 50,000 feet and the cold and high pressure will have no effect on the rubber expanding.
