Of the printers you mentioned and that we carry, the Ultimaker 3 is going to fit your requirements the best as far as reliability and stability are concerned. It's a solid machine with a good UI and mechanics. Not to say that the others aren't, but for the money, the Ultimaker 3 is the clear leader.
There's not really a drop-in solution for what you're looking to do, at least with an Airwolf printer. Lasers are complex machines, and can be dangerous if not properly designed and built. For this reason, you'll probably not want to try anything with a laser on an existing 3D printer, but rather build a machine that's meant for laser cutting, like the Lasersaur: http://www.lasersaur.com/
Another project that is good as a 3D printer or CNC is the Mostly Printed CNC, which uses a Rotary Tool as the tool head to cut or engrave: https://www.vicious1.com/assembly/
Turns out that the idler arm is broken. My last extruder assembly had the same problem and I printed a replacement on my MakerBot Printer using PLA. The design is still loaded so I am printing another. I love Open-Source printers!
don't worry, just the 2 rolls of filament (polyplus pla) that i had were bad... bilby3d stuff works fine
EDIT: that's not it. with the bilby i was trying to print at 210˚, but it would only preheat at 220˚... i think that the rafts that started at 220˚ and the part being 210˚ was what made it work... anyone have any ideas/support for me?
I had a problem with the part sticking too well to the BuildTak surface when using a 110C bed temperature. The BuildTak developed bubbles over time to the point that I couldn't use it. I pulled it off the glass and switch to WolfBite. This stuff is awesome. Prints stay put when building but release automatically when they cool.
Are you using the same settings for the red as you are the other filaments? Individual spools can have different thermal properties due to dyes and such, so if you haven't already try printing the red at a higher temp than the others.
ok right off the bat lets check extrusion caliper or decent ruler manually heat up hotend to current filament temperature then remove the bowden tube pull slowly the tip of filament will be multon. next cut the filament off flush to the end of tube.
with hotend still at temp you should be able to use manual control and extrude a given length. extrude 100m then measure you should have a 100m length of filament stick out the end of the bowden tube let know if under or over and by how much.
if havent altered any settings it should be very close but its one of easy items to check.