Asg M40a3 Technical Help!

[Jonnymet]

Hi all! I need some advice.

Over a year ago I purchased an Asg M40a3.

From day one I've had a problem with it seriously hooking to the left. I contacted the supplier many times without any replies. 

I've replaced the inner barrel to eliminate barrel rattle with a tight bore barrel and at the same time I've replaced the spring for a higher powered.

At the same time I had to dismantle the hop unit to replace the barrel, refitted the hop rubber and reassembled. The hop unit has also been dismantled a second time to check everything is OK. Sadly it is still doing it with no change for better or worse.

The only thing I can think of is changing the hop up unit itself. I can't find any reference online for an upgrade. People have said the VSR10 unit but I can't find one or have a reference to go from.

Does anyone have a link for an upgrade or have any solutions?!

Photo below of the unboxing!