Honestly, if you live in a terraced house, you're going to hear your neighbours from time to time. That's just part and parcel. If they're so sensitive to it, they should consider moving to a detached home or looking into soundproofing.
I live in an end terrace. I can hear my neighbours and their kids, and I'm sure they can hear me bopping about the place. It's just life. Yes, sometimes their kids can get a bit noisy and my DP has nicknamed them the baby elephants for how loud they walk but it's all in good fun and I'd never dream of banging on the walls or going over and complaining.
So long as you're not holding all-night raves or making unreasonable amounts of noise at unreasonable times, I can't see how on earth they can complain.
I would, however, to attempt to keep the peace, try and tell your DS and his friends to not race up the stairs. I get it-kids will be kids-but if they're especially sensitive to noise and prone to being dickheads about it-it could be a small adjustment that can be made on your end to appease them.
But they sound like people who will complain if they hear you sneeze in the middle of the night. Perhaps ill-suited to terraced living.
Continue as normal-you and your kids have every right to enjoy your home. If they do come around again, just politely advise that you're not making unreasonable noise, and if they have an issue with it, they can look into their own soundproofing.