I have completed an install of a LokSound Select Micro into a Kato Amtrak P42 Genesis. Along with some of their other modern wide-body locos, these are fairly easy to fit, with plenty of room under the shell. What makes this install different is that I have "activated" the two "logic level" output functions on the decoder (Aux 3/4), to allow for 6 functions. Why 6, well, this way I could have front / rear directional headlamps (2); front / rear directional red marker lights (with independent off from headlamps) (2); and proper flashing ditch lights (2). To utilize the logic-level outputs, one needs to use a switch transistor, where the decoder's output is the "gate", and when the logic-level is "on"(+5V), and path is created between an output (really a sink) and the decoder's ground (-). For those not interested in soldering itsy-bitsy electronics, Streamlined Backshop has a pre-made, 1cm x 1cm board which supports this function. However, for this install, I went with a smaller solution, a two-channel (handles both Aux3 and Aux4 in one) chip (FDV6301N - available at DigiKey). This first photo shows my initial test setup of this chip, wired to a LokPilot V4 Micro. The transistor is the upper left chip, and there are 1/10W 10Kohm resistors hung on the inputs (green and yellow wires) to the chip from the decoder. The grey wire is the decoder's ground. The output of the chip goes to the two big resistors to the mini board, with two LEDs, and the decoder's blue wire (common +) For a LokSound Select Micro, these extra functions can be found on the bottom of the board. This photo shows the connections. In this photo, the Orange with Blue dots is Aux 4, White with Blue dots is Aux3, and the gray with black dots is ground To use this little circuit, I cut a small square of 0.02" styrene, just larger than the chip and solder points, and then mounted the chip using Bondic (UV cure adhesive). This also let me encapsulate the solder joints in a very small package (less than 5mm x 5mm). As mentioned, the key for all of this was to enable the front and rear red marker lights, with the ability to turn them off independently of the headlights (headlights must be on for the markers to be on). I had read many posts of people not adding these marker lights in N-scale, as it would "require shell modification". Well, actually, no it doesn't! The little red plastic pieces Kato installs can pull out quite easily, and there are even holes already available to run the LED wires through. Here is the rear housing assembly from shell. You can see the rear headlights in the center, and the two 0603 SMD red LEDs I have installed. They are mounted right where the holes in the shell are, and the magnet wires go through the holes that Kato's plastic piece mounts in and here they are, lit Similarly, here is the cab/light insert from the front of the loco. You can see the two LEDs mounted at the bottom of the cutout, and the magnet wires going through the (removed) plastic insert mounting holes. I wire these red LEDs in series. In this photo (sorry for bad contrast) of the underside of the cab detail piece, you can see the two ditch lights with their cut light pipes, a 1206 warm white LED mounted to the main light pipe for headlight and number board, and in the bottom left corner, a small piece of circuit board that I used for the series connection on the red lights.