Would this be a good combo, or would one just blurp out the other. Looking to add more firepower so people jump twice as high! 
Time for a ship horn!
I would but i cant give up my bed space. Its either a p3 or a k3
I have both K5LA and P3 on my silverado. The K5la (All bells are facing forward under cab) will make people jump or duck and the P3 is not quite as loud and faces reward for the people that like to follow to close. I love the sound of both but the K5s are brutal. In your case the K5 would be better with A fast 1/2 inch solenoid mounted close to the horns for the the instant honk. If you check my sig, In the right rear fender well in front of the tire where the cheap chrome horns are or were, is where I put the P3s facing reward. Good luck in whatever you decide… Rex…
Put two sets of k5s one facing forward and 1 backward. That will get some attention. LOL