@tombo131 You could try the SpringCo ppq/q5 spring kit upgrade. Ive used it on the polymer version for over a year and love it. I just got an SF and installed it on that too, improves the weight and feel quite a bit in my opinion. Others have said that this kit causes issues with the dingus safety, personally I have not experienced this yet but it probably depends on how you grip the gun. There is a youtube video on how to install the kit, not too complicated, only two springs. I dont know if they have the kit direct on their website, I had to call and ask for it. Only $20 ish if I recall.
Would you mind telling me what exact spring you used on the recoil system? Is there any modifications or tricks to installing it?