The last point is really important. I find myself doing it more, and yelling at my gunners who are also looking down more. Be careful what you wish for, it might get you shot, haha.
I feel High G gives the Lib a lot more agility, but the more and more I see ace's fly the more I realize that High G and Precision are crutches for those who don't truly understand the Lib. You're not going to out maneuver an ESF with High G or Precision. You might be able to save yourself from slamming into a tree with High G, but it was your fault for choosing that angle of approach to begin with. Racer will at least allow you to close the gap, or increase it much better, while also being the better complement to Afterburner too. Unfortunately I've spent 700 certs on High G already and will need to spend another 700 on Racer.
It's good for running people down and running away. You start to lose out when you're engaging in close range fights though. I couldn't have done half the stuff in this video that I did if I were running Racer. No, they allow you to do specific maneuvers that simply aren't possible with stock or Racer.