I'm surprised a search didn't turn up anything, but the problem I'm having now is that my bike's headlights are WAY too high.
Did I say W-A-Y too high?
Like, when I flash the high beam I can see it lighting up the tree tops ahead of me.

Now, the manual says the adjustment is to be left to the service personnel.
Is this so?

In case it is, should I worry that they're going to do irreversible damage to the bike that may cause vibrations or other inconveniences? (like breaking silicone seals, glued stuff, whatever)
My bike is new and I'll live with the unusable high beam if that means keeping it from getting any weird noises or vibrations.

Thanks in advance!

There's going to be some form of adjustment screw on the back. Whether this is in the form of a turn-knob or a screw head, I'm not sure. I know that both the pregen and newgen (from owning at least one headlight off of each) both have some form of outside headlight adjusters to make aiming possible without taking anything apart.

Search the back of your headlight for knobs/screw heads/writing. The newgen headlight had plenty of writing to label what each adjuster is; pregen, not so much. I feel that the 300 will be labeled.

There is a screw on each side to adjust each individual reflector. I had to do this when I did the projector retrofit. Get a buddy to help you. If I remember right, you'll need a box wrench or ratcheting wrench but can't remember what size.