stock 12 bolt a little stronger than stock 9"
12 bolt can be beefed up cheaper than 9"
both require gears, spool , axles, and housing ends, but 9" requires beefier center pot, also bracing and inside housing welding is a good idea.
A dana 60 would be stronger than 12 bolt or 9" with comparable axles/spool/ gears.
If money is no object, then fabricated 9" housing with all the goodies would be very strong, but would it be stronger than the dana?? dont know all the big boys use the fabricated 9" or those modular designed ones.
Fabricated 9" look trick under the car, dana and 12 bolt it seems these days are passe'
In my opinion a dana 60 with axles/spool/gears would give good service in almost any car running down to 7s, or quicker if the car is light.