Yeah, I saw that 500SLC on their UK website, but not the US site. They had horribly little information. I thought the R107 had taller gears, like the 2.47's used in all the 116 and 126 applications?

You're right, though, MB used different carriers for different gearsets, rather than shimming the gears. I think clearances are so tight in there, that a universal setup may not have worked. (?) The 2.47 LSD units are fairly common in junkyards now, but not many people are interested in tall gears like that. I know I'm not!

It should be interesting, though... I'd ship the W124 210mm open diff to Quaife and let them figure out if they have something which is a bolt-in. The lifetime warranty is nice, and the price really isn't that bad ($1500?), compared with the fancy $3-$4k Japanese units I've seen. On a budget, the factory clutch LSD ain't bad, and on really tight budget the Phantom-Grip would at least be worth a try if you could get it for more like $200 instead of $500.