Cybergun M4 CQBR Hop-up

[RealGerf]

Hi,

I am looking for advice on what hop unit and inner barrel to get for my Cybergun CQBR M4 (leaving the barrel extension on). I was thinking guarder or TM for the hop and probably the guarder 6.03 barrel.

My friend and I both bought the same exact M4 and he has since upgraded the hop unit and inner barrel. His magazines now don't fit properly and he has to tape them up to keep them in and it's all very fiddly. He bought a madbull hop of some type and I'm not sure which barrel.

I am looking to avoid this problem!!