If your choice were to be a swap, you are entirely on your own; but with this caveat:
measure carefully the overall width across the exhaust manifolds/headers.

Mike D.'s option of the 560 is the least cost alternative in a M117. Consider also the 420 M116; it is the low deck version of the M117. In either case the installation of the complete KE-jet system will either keep you out of the bars for many nights, or send you there on a regular basis.

A 560 sourced from a W126 chassis will come with an exhaust system that is not compatible with the 107 chassis. An exhaust system from a 560SL would be required.
OR
If a 420 M116 is used, your existing exhaust system will bolt on. [The heads on the 560 have an exhaust manifold bolt pattern that differs from that of your 450 & the 420.]

The 420 as delivered in the US is a bit detuned from the euro version, yet is quite a bit tuned up with respect to the US 450.