Messerschmitt Me.410, part one

The forerunner of the Me.410, the Me.210 was in development since 1939 but, as it proved unstable, it was never taken into consideration for mass-production. Layout modifications performed in the Me.210C and D versions, led to the development of the Me.410 and the Me.310 in parallel. This last one, which was almost identical to the Me.410 in appearance, was discarded in favour of the Me.410 as it was already showing better results.
The main difference between the Me.210 and the Me.410 layed in the introduction of the larger and more powerful Daimler-Benz DB 603A engines which could deliver up to 1730hp of power (1290kW). Thanks to that extra power, maximum speed was increased up to 625 km/h (388mph) improving in a notorious way the rate of climb, service ceiling and cruise speed which jumped to the notorious speed of 579km/h (360mph). Payload capacity was also improved as it could carry more load than could fit into the bomb bay under the nose. In order to take advantage of the extra power, shackles were added in the lower part of the wings to fit an extra amount of bombs. The changes added a total extra weight of 680Kg to the Me.210 fuselage design, but thanks to the extra power of the engines, the design could lift it without any problem.
The new version featured a lengthened fuselage and new automatic leading edge slats which had been already tested in the Me.210 and proved to dramatically improve handling. Those slats were the ones featured in the earliest production models of the Me.210 but were removed due to poor handling. In fact, when entering a steep turn, they had a tendency to open due to the high angle of attack, analogous to the opening of the slats during the landing approach, problem that was already present from the earliest versions of the Bf.109D. This problem had to be added to the long list of other problems that kept the aircraft from flying smoothly.
Anyway, when the problems with the general lateral stability were addressed, the slat problem was neutralized. The wing panels of the earlier Me.210 were designed with a planform geometry that placed the aerodynamic centre in a rearwards direction, when compared with the Bf.110, granting the outer sections of the wing planform beyond each engine nacelle a slightly greater 12.6º leading edge sweepback angle than the inner panels' 6.0º leading edge sweep angle. This resulted in unreasonable in-flight handling characteristics in the original Me.210. Therefore, the new Me.410 design had outer wing panels' planforms revised to bring the aerodynamic centre forward when compared to the Me.210, making therefore the leading edge sweepback of the outer panels identical to the inner wing panels with both having identical 5.5º sweepback angles, improving handling that way.
The production began in 1943 and continued until September 1944 with a total of 1160 exemplars having being manufactured by Messerschmitt in Augsburg and Dornier München. Unlike its predecessor, the Me.410 was liked by its crews when arrived, even if its performance wasn't enough to protect them from the high numbers of Allied fighters present at that late stage of the war.

Sources:
1. https://en.wikipedia.org/wiki/Messerschmitt_Me_410
2. https://forum.valka.cz/topic/view/179982
3. https://forum.valka.cz/topic/view/179990
4. Salamander Books - The Complete Book of Fighters