Both play large roles in the flight performance of an airplane. So it depends on how you measure the impact. What I mean by that is it depends on whether you are talking about performance in terms of climb rate, top airspeed, takeoff distance, landing speed, or some other quantity. It also depends on how much margin you had in terms of excess thrust (to overcome drag) or excess lifting capability (to overcome weight) to begin with.

As it is stated, I don't think there is a clear answer to your question. What type of plane are we talking about here?

Cheers,

Rich