Marantz PM-15s2 Limited switch

Thanks for your input millercarbon

Didn't know interconnects, speaker cables and power cords could make such a difference.

No. Does not work that way at all.

Wpc is measured, while "loud" is subjective. Some amps simply sound more powerful than they measure, for example.
 
But even if you go by measurement, the difference in terms of decibels between 70 and 90 watts is probably only about 1 dB, ie barely noticeable.

As a general rule you can disregard power differences less than double. Even double the power the difference is only 3 dB. In other words your 70 or 90 watt amps would need to be around 150 watts to even begin thinking about power.

All of which is almost beside the point. What really matters is not how many watts but how good. Because even playing loud the vast majority of the time the output is only a few watts. Which is why Robert Harley famously said, "If the first watt isn't any good, why would you want 200 more of them?" The sensible thing then is to buy the one that sounds best, period. 

Since you already have a pretty nice amp it makes no sense to change until and unless you find one that sounds a lot better.

Take whatever you were thinking of spending and use it to upgrade your interconnects, speaker cables, or power cords. Or buy a Blue Quantum Fuse or two.