Look at the deminsions compaired to the return opening on your furnace or air handler. Choose based on wich one will require the least transition work to mate up to your furnace or air handler.
The pressure drop for both is acceptable for a 2 ton system. The 1400 will have a higher pressure drop because it is smaller, but it is likely a better fit.
If more government is the answer, then it's a really stupid question.
Office and warehouse in both Crystal River & New Port Richey ,FL
Try to be sure the ducts design ,includes the pressure drop ,of the filter you choose,it often doesn't.
Example: builders model has "X" size return duct,customer upgrades to better filter,when his house is built,the duct is the same size as the model,and air flow is very low.
I'd use the larger one ,if space allows,less pressure drop,longer time between changes.
Example:4 ro 5 ton system,,returns on both sides of the indoor unit,put a filter in each side,instead of using a single return.Costs a little up front,but now you change two filters once a year ,instead of one filter twice a year.Pressure drop is a lot less.All properly sized to make it happen.
What do you think the maximum air flow a Spaceguard 2200 should handle before you should add a filter to both sides of the furnace. I have been told several times that a dual filter set up is for 5 tons and higher. If I am interpreting your post correctly you would consider this set up for 4 tons as well.