The idea behind this build was to enhance features of a 4'' Long Range explorer by combining it with stable and powerful low-RPM motors trying to get a close-to-5inch dynamics together with longer flight time.
GPS-security and ability to put a small HD camera on - were the must-have.
Below or close to 250g - nice to have.

The motors came from my Protek35, which I was not really impressed with, but those motors are light weight and good torque combination.
Although the choice of frames was limited due to most of the 4'' frames have 9mm motor base, so I stayed with Diatone - well known and offering option for 12mm motors.

Just starting the build I realized that Diatone L4's weakness was a back TPU part, which I had to replace with custom printed back case (thanks to user lipa46 who placed the model on Thingiverse). I printed it in hard PLA plastic, which made the frame stirdy and allowed to locate components safely. Mine GPS did not fit, though.

I started with default choice - HQ Prop 4x2.5x3V2S,. but switching to more aggressive props (4043, 4032) brought completely different dynamics - brisk and crispy at low noise, but less inertia comparing to 5-inch, of course.

Another advantage, that this build can consume big range of batteries - from 4s 850mAh up to 5-6s 1500mAh, not killing it and not being killed.
After proper tuning - motors are hardly warm.

Overall, hard to express how happy I am with this build, and can't stop enjoying it!

Flight time - 6-9 min on 1500mAh, depending on style.