Does anyone think this will work to help make the arms stronger.  I was thinking of buying the kit.

Arm reinforcement plate

I would like to have you guys thoughts on this.

Thanks

Looks like they'd do the trick. However, I've not seen many motor mount cracks being reported, only seen the one, and who knows if they were 'self inflicted'.

It shouldn't hurt, I'd just be mindful of screws vibrating loose because the blue thread-locker is no longer in place - unless you reapply it.

The plate will work just fine. The only thing I would add is that the area between the arm and the plate should be bonded using an epoxy adhesive. That way the entire shell arm carries the load not just the motor and two shell arm hole area.

The mounting plates for the removable prop guards does the same job minus the two additional pick up holes.

When I first bought my P3P back in April I bought a set of Summitlink Snap On/off Prop Guards since I was new to flying. The base piece that accepts the prop guards acts like these reinforcement pieces above. Now that I have been flying quite a bit and more comfortable I usually don't use the guards. Cost is similar to above but you get an added bonus of the guards if you have a situation that might be prudent to install them. Just a thought.