Oh no, I'm very happy with the out of box performance. I only have 3 upgrades planned and these are mainly for longevity.
- The sixG brass nub as you mentioned
- G&P Aluminium buffer to replace the plastic one
- and something to increase the fps a little. You guys who are more experienced with this platform can tell me what that may be.
The only external part I didn't like was the charging handle. I found that my grip would slip off when using it under pressure; Something a Raptor charging handle will fix due to it's hooked ergonomics.
In regard to the pistol grip; I can tolerate that for now although it's not the most comfortable.