H4 headlamp on a 1979 Vespa Rally 200

I am looking to put an LED or really anything bright headlamp on my 1979 Vespa Rally 200.

I was thinking of using this

https://www.sip-scootershop.com/main/base/Details.aspx?ProductNumber=57240000&_language=en

 

It says it needs minor modifications.

Anyone know what they are and everything I need to do this ?

Thanks