The Merc turbo is a 45 trim T3, same compressor as the VW diesel one but a bigger turbine section. The V-band thing unbolts from the turbine outlet leaving you with the standard 4-bolt T3 outlet that fits the stock T3, not sure about the K24. That V-band thing is Mercedes specific. Kinda neat looking but unless you had the downpipe to cut the other end off of, you won't be able to join it to a traditional V-band.
The Volvo turbo has a different manifold mounting flange. There are adapters to make them work on a standard T-3 flange though. The Volvo turbo also has a .42 cold side, (same as VW and Merc) but I'm not sure on the turbine side what they are. The Merc turbo actually spooled up about the same as the stock T3 did, maybe a tad later but not too bad. Mine blew up because apparently I didn't rebuild it correctly.

Brendan