Yes, your rear turn signals will likely be dimmer and more difficult to see. Same may go for the front, but I haven't experimented with them.
The reflector for your front/rear/every light emitting optical fixture on your car is designed for a certain bulb. The light is emitted in a certain pattern and a certain location in each fixture to utilize the reflector/projector properly. When you move or change that pattern, you can easily have bad results.