Springman:
If you look at the photos on the eBay page, you can see that in addition to the light unit - there is a small box and additional wiring that needs to be used with the light - and that is likely not going to fit inside the small Savage headlight. It is good that the units have the little shields on the low beam - that is what cuts off the light from shining up into the eyes of oncoming drivers (vertical cut off).
I have been using a similar Chinese LED headlight bulbs, and I put them in my Cafe' bike for a test run - then eventually put them in my car and have been running them for more than a year. They are brighter than the stock bulbs - but the light pattern is a bit uneven and it makes a spotty light pattern on the road...some spots are brighter than others. I am finding this is a common issue when you put an LED in a reflector designed for a filament bulb.
This is likely the next bulb that I am going to try, and I believe you can get it to fit in the Savage headlight. It looks to be pretty small, ADVmonster claims it has the best light pattern of any light they have tried.
http://stores.advmonster.com/h4-r3-led-headlight/