This router is variable speed, can I use an additional speed reducer to slow the speed even further if I need to?

Thanks for the question. The 1617EVS router has a no load RPM of 8,000-25,000. That can be adjusted with the variable speed selection dial. Unfortunately, we don't recommend adding new speed dial because the wiring and specifications may not work properly. For further assistance, contact us at 1-877-BOSCH99 (1-877-267-2499) from Mon-Fri 7A-7P CST.