No-one said conversing with strangers is in itself scary, or that you have to go over shouting and swearing, that is simply your e-tough guy persona talking. What I and others are saying is that these guys clearly already know that they are making noise, working on vehicles with heavy machinery at unsociable hours and then driving them fast and loudly past houses late at night, and they don't care... you would have to be extremely naive to think otherwise. If the OP goes over and talks to them politely, and they politely tell him to get lost, or don't stop the noise, then when the OP inevitably escalates it to the council they will immediately tag him as the person who has done so and potentially resent him for that as the situation escalates.
Of course, a quick and friendly chat could sort it out. However, as many of us with some life experience behind us know, it can also go the other way. Reporting it via official channels, when he has every legal right to, means he avoids all of that potential drama, especially when he lives so close by.
I also find it rather amusing that people think that a person only has to resort to something as crude slashing tyres or keying people's cars to make life more awkward for them, because I assure you that there are many more subtle and fully legal ways for someone with a large presence in the local community to make life uncomfortable for someone.