The wing tips were angled downward 35° to reduce the lateral stability, the wing was redesigned to detach from the fuselage, and the aerodynamic balancing of the elevators was reduced from 24% to 20%. The fuel capacity was increased to , the cockpit was widened by  and fitted with an ejection seat.
All these changes added  of weight and increased drag which reduced the aircraft's top speed by , and slowed its time to  from 4.8 to 7.2 minutes in comparison to the unmodified aircraft. Given that a higher-performance design, the Aircraft 156, had already been submitted for state acceptance trials, Semyon Lavochkin decided not to continue the development of the 150M.