I just tried to compare S3100 and S3100MKII.

Both use the M150HS Woofer and both use the H2600 Horn.
The difference I found is that the S3100 use the 2426 and the S3100MKII use the 275ND Driver.

Does anyone have the crossover schematics of BOTH available? A comparison would be interesting!
Part No. of the S3100 schematic is 316398-001