I've had good luck with standard bulbs but ...
I replaced my Hella stock lamps with a pair of Hella-made halogen lamps that use the same bulb but throw out much more light. The reflector design of the stock lamps leaves much to be desired.
Also, if you keep the stock lamps, be sure to protect the internal wires and coil them in the rubber boot. I highly recommend installing a pair of the fuse assemblies made by our friend, Kirb. Go around and tighten the hell out of all fasteners that attach the engine guard and lamps to the bike. This quelled a lot of vibration for me.
Finally, be aware that the Big Fuse that blows when the lights short out and kill the alternator is located behind the plastic cover on the right side below the seat. A spare is provided on the holder itself.
I lot of posting has been made concerning the auxiliary lamp issue on the Stelvio. You may should do a search.