Development code D4Y3-S (or Suisei Model 33E) was not discovered in the IJN official documents.
D4Y4 Suisei Model 43 – Final production variant. Bomb load increased to 800 kg (1,760 lb) with the main bomb semi-recessed in the bomb bay.
It had 75 mm bullet-proof glass in front of the canopy, plus 5mm and 9mm thick armour plates fore and aft of the cockpit.
The fuel tanks were also given added protection, and the movable rear machine gun was removed.
The addition of five RATO boosters was considered: three in the lower-bottom part of the fuselage and two on both sides below the engine. Generally, the D4Y4 is often recognized as being purpose-built for special attack operations.
D4Y5 Suisei Model 54 – Planned version with Nakajima Homare radial engine, four-blade propeller, and more armor protection.