beefing up a bronco's suspension

[bluelx347]

I recently bought an 89 bronco full size and i want to put a super duty suspension on it. I do not want to lift it only put stronger springs in it. I am going to be plowing it and have a salt spreader on the back. I will also be carrying a lot of salt in the back and need springs that won't just give in with all of this load. Can i upgrade the suspension to a f250 or a f350's springs. I also want to know if people recommend the air bag suspension that attaches to the springs. If any one has any other recommendation on how to increase the load capacity of my truck let me know. Thank you Dan