I see that MDC has a few undec HOn3 2-truck Shays offered on their web site for 79.99 free shipping, reg 159.99; half price might be too good to pass up!
I think the MDC shay will always be noisey to a degree , depends on how fast you run it.I have not used the NWSL gears , but i cleaned the plastic gears and tweeked the driveshaft using the directions given in the excellent book Jeff Johnston’s
MDC Shay Handbook.
Although it is noisey running at a fast speed i usually keep it running protypically slow and the noise made at that speed is acceptable limit to me
The books shows step by step instructions on how to build the 2 truck shay as the kit and a enhanced 3 truck shay by remotoring and regearing along with tips on detailing and weathering.