The MLs have an impedance of .52 ohms at 20khz. Technically they need a powerful solid state amp that doubles output at 4 ohms and again at 2 ohms to drive them properly, but many people find that a lower powered ss or tube amp works for them. I'd guess that the increase from 75 watts to 150 watts would be an improvement but I would audition before buying.
Here's a link to an earlier discussion about this subject: