I've got 2 WE M4 based builds , which is fundamaentally the same platform. I've had no failures with either despite a huge number of rounds through them. As a general rule I replace the barrel with a Maple leaf crazy jet and the rubber with a M/L 50 degree one. The rubber is more important than the barrel tbh. You'll need an NPAS or restrictor disk to get the power level down to site limits, I've got both and am happy with them both, mine hated the adjustable power nozzle thats available . On one of them I've got RAtec parts in the trigger nbox, but that's just 'cos I had them (they'd been sat in the draw for well over a year ) rather than because I had any issues. The boly lock can sometimes be tempremental, although I've never had any issues with mine.
Basically I'd just replace the rubber and fit an Omega nub, maybe do the barrel if you want, then just use it until something breaks. Mine happily run Nuprol Red all year round unless the weather gets very hot like this summer then I switch to green.
For games I run 5 mags and a speedloader, i can easily get two BB loads from one gas fill so that gives me about 300 rounds which easily last me an hour game.