Note that if slower RPMs is what you want, you can get a spindle without the need for an HDZ (which for wood work, honestly, is largely overkill) if you stick with smaller 800W models. This is a great thread about that, and those spindles will fit the stock router mount diameter.
However, you should consider/try going to higher RPMs instead, the higher the better since it decreases the cutting forces. The only catch is that of course you have to increase feedrate accordingly to stay in the sweetspot for chipload. I spent almost a year in the “12k comfort zone”, but then @gmack opened my eyes on this topic, and since I upgraded to a spindle in the meantime, it’s so quiet that using max RPM (24.000 in my caseà is not a problem anymore (I remember trying to use max RPM on my Makita…oh my, the neighbours did not enjoy that very much, and neither did I)