I bought the Frankenstein X3 from QuadMcFly (lots of builds here), but I cracked the frame in a crash and bent the caddx F1 metal bracket pretty quickly.

I wanted a 3" quad with a carbon fiber top plate and a 4mm bottom plate so I thought I'd try the Loki X3 REC frame. I slammed the top plate using 20mm aluminum spacers (the default REC frame height is ludicrous). I also bought and installed 8mm long M2 socket head cap screws on the motors so I could sandwich the TPU arm guards between the motors and frame. Unfortunately, I had to replace the ESC wires with longer wires because the Loki X3 REC has a slightly longer wheelbase.

I took the opportunity to coat all of the electronics liberally with silicone conformal coating. I haven't tested it yet, but this quad should be able to fly in the rain.

This little guy is running multishot, which is nearly indistinguishable from dshot600 in my experience, though maybe a bit sharper in response. The final weight of 154g is sluggish on 3040 props. It doesn't respond immediately like it used to on a lighter frame. I definitely feel the inertial mass when cornering and have to compensate for it.

UPDATE: Tried some Gemfan 3052 props (pink props in the photos). I think the steeper pitch does an EXCELLENT job restoring the lost agility due to increased weight. Cornering probably still suffers a bit, but it feels very fast again. Motors come down cool as cucumbers.

UPDATE2: Having flown this for a few days, this is hands down my favorite quad for tight quarters right now. I fly it with short bursts of the throttle to change direction, absorb momentum, and accelerate. It's like a hot pink wind bunny hopping across the yard. If I need to and I'm very very careful I can fly it stable at slow speeds, but a quick pitch forward and a burst of the throttle launches it all the way over my house or across the yard. My son pointed out that it hovers at about 1/4 to 1/3 throttle, which is just where I like it. The Gemfan 3052s are just insane at delivering power from the 1306 motors. It's quiet (motors and props emit a fairly low pitched noise) and relatively unintimidating to passersby (looks like cute pink toy). Unless I'm really flogging it, I get about 5 minutes of quick crisp flight time per 500mah 4S battery. I'm thrilled with this build!

Custom parts:

• Custom designed and 3d printed FPV camera mount in PLA. Adjustable from about 35 degrees to 90 degrees with the Caddx F1.
• TPU arm guards found on thingiverse and printed on my printer.