axle swap

in my 89 laredo i would like to run 33's on 6 inches but i have a d30-35 setup so i was wanting to know if you could swap out axleshafts to gain some strength rather than putting in new fr.and rear.and also what is this i hear about plastic inserts in you hubs so water and dirt won't get in your axles?thanx

1st) you dont need 6"s of lift to run 33's

2nd) alot of people here run 31-33s on the dana 30 and 35 although it isnt smart/ cheap to run anything bigger

yeah but with "6" i can go bigger later.