Good old Optimus Prime. After I had built a transformer for the second time, corrected the colors once when I had enough red bricks again, I got back to this kind of model again for a third time to give it a final (?) facelift.
The reason for that being the fact that while I was building the cabin for the black Tyrone Malone Transporter, it came to my mind that this newly designed front would look good on the transformer also.
O.K., I must admit that this cabin has no "real" windshield and the front bumper is completely different, too.
I also changed the tires from the old 20x30 technic wheels to the air-filled ones of the 8479 set, which looked a lot more realistic due to a finer profile.

I never had a real Transformer, the poster at the top left was my only reference. My model differs from the real one in terms of the headlights still being at the front when the model is in robot form (instead of being "behind the fists"). This may be inaccurate, but I liked it better that way.
The fists can be stored inside the two doors at the back of the cabin and the head can also be tilted inside. The only additional separate item is the blaster.

All versions on one page. To the Left is the first incarnation with smaller wheels. The second model is below (transforming in 3 steps) and to the far left (with corrected colors).
The above model should be final, but who knows.