70-73c is harmless to your CPU, and it will run at that indefinitely without issue. Throttle temp set by Intel for your CPU is 105c, and you're still 30-35c away from that. Unless you're concerned about noise, I wouldn't bother.
Yes. I'd definitely recommend an aftermarket cooler. 70-73 isnt the WORST temp, but it sure isn't good. Pretty high. Running at that hot of temps will really put a wear on your CPU over time.
70-73c is harmless to your CPU, and it will run at that indefinitely without issue. Throttle temp set by Intel for your CPU is 105c, and you're still 30-35c away from that. Unless you're concerned about noise, I wouldn't bother.