FX Biathlon... Anyone?

[Mtl_Biker]

Does anyone here have one of these?  FX Biathlon in .177?

I'm trying to find out some information about it and my searches don't turn up the information I'm looking for...

In particular, when the specs say the power is adjustable from 7 to 36 joules (that's about 5 to 26 fpe) I'd like to know HOW it's adjustable.  Is it something the owner can do easily, or something that's done by the dealer one time (for a certain purpose or country limitation)?

The sound level of the gun is also something I'd like to hear about.  I'd imagine that at lowest power it would be quieter than higher, but how does the sound compare with other rifles, particularly the Air Arms S510.

With my recent interest in 10-meter shooting (with a local club) the FX Biathlon with optional (and quite expensive Gehmann Diopter sight kit) might be excellent for that.  Plus by putting a scope on it and upping the power, it could be used for field target or pest control.  Sounds ideal so far.

Input would be great!