I can't seem to get my slic3r settings right for 100 or even 150 microns. I use the same settings for 450 down to 200 microns and all my prints come out great. At 150 or 100 microns, my external perimeters look pretty good. However, my infill is piling up and then the nozzle is bumping over it layer after layer. I tried to play around with the advanced settings but I don't really know what I am doing there. I did try to increase the speed of infill but that didn't seem to help.

Bridging, overhangs and sparse infill begin to fail at these layer heights due to the small amount of material that is being extruded. I can get decent .05mm and .1mm layers but I am running a 0.25mm nozzle.

I find the larger the nozzle diameter the lower you can go as a result of the volume of plastic being extruded by one step of the extruder motor. You can try the calculator in my signature to get the setting I use. I print down at 0.08 whenever I need really smooth curves. Also part of your problem may simply be Slic3r, I recommend trying Kisslicer or Cura before wasting too much time.

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It's all about volume control. Check your E steps/measurements. Then go on to your extruded plastic measurement. In most cases, it comes out thicker than your actual nozzle diameter. Next go to your filament thickness. Measure at least 3 different spots over a large length. Input your average thickness. Not all filament comes out the same whether it's 1.75mm or 3mm.