Skip down if you just want to see what's changed. However, for those that enjoy 3d printing their own frames, I've included some the interesting findings that I've come across during my testing.

I've been continuing to test and have made some improvements to the my frame which was inspired by Dave_C's Calimero. If you look at the pictures of the Spark v1 or v2, you'll see each frame has two colors: a base color and then a "spine" on top in a different color. This is more than just for looks. I find the Carbon Fiber/PLA mix is more rigid and prints nicer than regular PLA. However, CF/PLA tends to break easier than regular PLA. So, I added a "spine" to support the frame that extends from the center of the frame and down the arms. This support has two purposes. First, it gives extra rigidity to the arms. Second, if this spine is printed in PLA+, the frame has much better durability. PLA+ is more flexible than both regular PLA and CF/PLA. However, it has superior adhesion than either of those. The PLA+ is a sort of "glue" that helps the CF/PLA from fracturing in crashes with the extra layer adhesion. I printed the spine in regular PLA, but found the PLA did not adhere well to the CF/PLA and would seperate when the frame bends past a certain point.

UPDATE for v2:
I remixed the tomoquads slingshot lipo system and created a sort of "lock and key" in the center of the frame. There's two versions of the frame: normal front to back mounting and toitlet tank style. The fit feels very secure, much better than the V1's lipo holder, and barely changes the overall weight.

The Reason: I normally use rubber bands to hold my 450mah 3s lipos in place when I use Carbon Fiber frames. However, with this 3d printed frame, rubber bands don't fit around the arms very well. V1 had the lipo holder screw into the frame with the same bolt used to hold the canopy on. However, I was never completely happy with this. The TPU would start to fray around the m2 screw after repeatedly swapping lipos in and out.

Video explaining the lipo mount...

Lastly, I'm trying a new PLA+ filament from hatchbox that changes colors in the sun. Here's a video showing it changing from a clear/white to a purple