I am going to buy a new Cooler for the CPU, but i was worried about the hot air, which will be spread into the case, with ne new cpu cooler. So i wanted to improve the Exhaust.
1x Intake and 1x Exhaust are connected to the PSU (Fansplitter should arrive today), and 1 intake is running on 8.4V (Temp dependent regulation)
Max rpm is 1200
The heat produced is dependent on the cpu and a different cooler won't change how much is produced. A better cooler moves the heat away from the cpu more quickly but the heat will still be dumped into the case. This is normal and shouldn't be a problem with the case fans you already have. In fact, warm air from the cooler is still better than no air at all. If your case fans aren't too noisy, there's no need to replace them.