The Abus Granit is certainly a much more secure lock than the Abus 83, as it's steel body instead of brass. However, I was looking for a decent "bang for the buck" lock to recommend. $32 for a difficult-to-pick keyway and shielded shackle is pretty good.
But certainly if you really want to secure a lock box with cost as no objective, then the Abus Granit is exactly what you want to go to.
Just a couple things to watch for though:
1. Not all of the Granit series have a shielded shackle. Even though the shackle on all of them is hardened steel that is really difficult to cut through, I prefer shielded shackles so that a would-be thief doesn't even try.
2. The minimum shackle diameter on the Granit locks is 11mm, which is pretty big, and they go up from there. Make sure whichever one you get will fit whatever you're trying to lock.
3. The locks are large in general, and may not fit in the designated space, especially with the shielded shackle models.
4. Obviously, there's cost. Minimum will be around $90 for a small one.
5. The Granit's use a disc detainer lock mechanism which is generally a lot more difficult to pick than standard pin tumblers. But not a ton more difficult. Bosnian Bill and Lock Picking Lawyer have developed their own tools that can make most disc detainer cores pretty easy to pick. Now, granted that's a specially-designed tool, in the hands of an expert. But just be aware that 4x the price doesn't mean a core that's 4x more difficult to pick.
If you'd like some of the highest security padlocks available, check out
Padlocks :: Security Snobs (I have no affiliation with this web site). They sell high-security locks that have been re-cored with one of several different high-security cores, including the Abloy Protect2, the only core I know of that has no publically-demonstrated picks.
