The Goodyear air bags seem to do well. Another trans cooler in series may save big money down the road.
When I picked up my '94 F350 twenty years ago the service manager ask if I was going to put a snowplow on it, I said yep that was the idea. He put another cooler on before I even took delivery. Twenty years and hundreds of tons of snow later all I have done is change the fluid.
They have some aftermarket brake packages for trucks but I haven't used them, may be all set if the trailer's are doing their part.
Don't get carried away with too much weight on the tail of the trailer or you might get carried away ! Can get real exciting real quick !