About the rust in the gutter,I want to elaborate...You won`t necessarily see rust up there.The body sealer can crack from age and the sun.This let`s water through and over time things get rusted from the inside where you can`t see it from the water`s path to the ground.
I discouraged air bags,mostly,to keep you cheaper.Air bags were first introduced to increase load capacity.But,what you`ll find available for drop-jobs aren`t focused on hauling capacity.
I`ve never seen drop spindles effect bumpsteer.They don`t change any geometry.They just relocate the spindle on the knuckle.Too much spring drop would cause problems.A proper 4/6 static drop will run you about $800.This would include adjustable panhard bar,shock relocators,KYB shocks,all four coils,and drop knuckles from Early Classics Enterprises.You can do it for a fraction of that but cutting corners(or coils
).