if you do this you will only need the mounts from your original rs box and the bolts, it all fits together ok.

but.. the diesel box is no stronger it just has longer gears, also it has NO limited slip diff,

the best option is to buy a recon rst box with better diff and shaft bearings and if you want the longer gears get a fith gear put in it from a diesel box. stay with the LSD tho...