Have you considered the Hella 90m modules? Available in 12v Main/Dip beam Halogen, Xenon, etc..........
Have a browse through the Hella catalogue - search via 'Universal', then select 'Lights/Signal System', then 'Headlight / Parts', and finally 'Headlight'.
Then click on Hella under the Brand Selection - et voila - fill yer boots........
A couple of alternatives I'm going to explore are:
1, As I've done on my truck which also has poor lights (to put it politely) even though I've replaced the original rectangular headlamps with clear polycarbonate lamps with better reflectors is to supplement them with a pair of fogs wired in with the dip and a pair of drives wired in with the main beam (see photo below). On a GS it could be powered by using a 35watt HID in the headlamp and then 35watt HID's in the fogs/drives, total power required would then be 105watts on main or dip. Not a cheap solution I grant you but what price being able to see?!
2, Clearwater lights from the US who have some LED's that are dimmable and run on dimmed power on dip and revert to full power on main beam.