YourAveragePlaneMaked posted a 23 piece airplane made out of standard blocks and unironically named it Make this little plane better. I accepted the challenge.

So keeping the original fuselage and limiting myself to using standard blocks and wings wherever I could, I looked at YourAveragePlaneMaked's build and found:

1) The center of gravity was too far ahead of center of lift: I moved wings forward
2) The tailplane is too small to have much of an effect: I enlarged both horizontal and vertical stabilizers.
3) The propeller is too small and too close to the ground. However to enlarge both prop clearance and prop size, the plane needs a bigger landing gear.
- I made landing gear legs out of structural wings. (As an unintended consequence, this also gives us a vertical pivot counterpoint for the vertical stabilizer so Yaw now at least halfway works like Pitch and less like Roll)
- I replaced the double landing gear assembly, with resizable wheels
- To have the front wheel in the center again, I moved the front wheel strut sideways
- Finally,I made the front wheel steerable for good measure

With this, I was able to increase the prop diameter from 50 to 71 (with he prop surface being pi/4 times the square of the diameter, this means the actual working surface doubled). With this I was able to cut the engine power to 350 Hp and still be able to cruise at a (for a sports plane) reasonable speed of 225 mph.
Nothing says however you can't increase tht power again to build yourself a flying hot rod).

Finally:
- Trying some landings I found that when braking, the front wheel digs in and lifts up the back wheels. To counter this, placed a shock absorber on the front wheel, and did lots of some start and stops and rough landings to tweak the strength and damper settings.

4) I found the ailerons are perfect size for rolling at decent rate but on the plane they look rather small. So I increased their size but in the XML overload editor decreased their 'MaxDeflectionDegree' from 35° to 20°.
5) Then added flaps for good measure, bringing the landing speed down to 120 mph
6) Finally did a little repainting

flying: The plane is pretty viceless except for it tending to loose its prop on a hard landing. With full flaps, it can take off at about 120 mph and with full throttle cruise at 220 mph. When taking off, deploy full flaps and trim 1/2 down. The plane will take off by herself at about 125-135 mph. When landing, approach runway with full flaps at about 25% Throttle or roughly 130 mph, keep throttle to actively dive towards runway, then cut power and keep nose up while plane floats down. On ground, use brakes sparingly
If however you want still easier flying, decrease the prop diameter from 70 to 65 or even less

Happy Landings.