The 80-82 diffs are no where as strong as the 63-79 iron units that have been custom built beyond a stock setup. I would take a stock iron unit over a 80-82 any day of the week. This of course is my own opinion, there are some out there that use them in 400-450hp cars and never had a problem & then others that broke the caps with a stock engine.
What I recommend is what I've built for many, an iron conversion built to application. You would need to find a good donar car to get the diff, brackets, shafts, and will have to modify the driveshaft. The iron diff will bolt up to the bat wing cover and there is a mod to that but nothing major. Look for a 71-79 diff to build. If you can do the work then you will save a lot on labor. The strongest 10 bolt vette diffs are referred to a super 10's and there are a few of us building them although the procedures used are not the same. It sounds like you already know about this and the 12 bolt. The 12 bolt will not work with your batwing so you would have to use an HD Iron cover and them fab up the mounts like the earlier cars used.
How much will it cost you? Ball park a super 10 runs $2800 and up, 12 bolts over $4000(less axles) complete a 12 bolt & axle kit is easily into $7000+
Rarely will you find anyone dropping that much into an 80-82 unless they are going to keep it for a very long time.
A common exchange iron unit is not what you want either because they are primarily stock (master kit & clutches) rebuilds and the weak areas are not addressed. The super 10s I build are in cars with up to 550 hp but that is a very subjective rating, all depends on usage, traction, and power.
Again it sounds like you have already done some research into this but I think the super 10 is what you need but you have to judge the cost vs usage. You may have an aluminum diff that will hold up only time will tell.
If you have access to a surface grinder, mill, lathe call Tom's and see if you can still get the 30 spline spiders, they're almost gone now and when they're gone it may be a long time if the same quality spiders will be available- if at all.
