Hi Phil,
I recently fitted an LED bulb (eBay special) for someone to a SuperDuke KTM and the results were much better than I expected for the no-make brand.
Installation was average, little space to work in the KTM headlight and the bulb has a sizeable internal fan however, the beam and especially the very wide spread were impressive.
On my own ST4s I went to HID which I found a good improvement on the low beam, a bit fiddly, 2 line boxes to install, but worked flawlessly for the 7 years I had the bike with it installed.
Found a thread for you here - good luck
https://www.ducatisportingclub.com/s...hlight=ballast