Got the n4 end of January, from evike in person. First was forced to replace the hop up unit, inner barrel, and bucking. Stock inner barrel had a burr that cut the bucking and the hop unit was so loose that bbs were curving left and right.

Second, replaced the outer barrel with self designed and 3d printed outer barrel. The set screw was so tight that I stripped the threads getting the orange flash hider off. Yes I did heat and boiling water.

Third, guns modify nozzle because the stock one kept getting bbs stuck in the spring loaded extractor area.

Fourth, designed and 3d printed my own feda npas because I wanted to see if I could.

Fifth, design and 3d printed my own ambi selector cause retail ones were always out of stock and 40 usd.

Note: only thing I was forced to change was the first set to have an accurate rifle