Mmmm......toughie, that one......

The twang certainly won't harm the gun and, as you say, you're happy with the performance.

But then, having shot twang free rifles, this may always cause slight annoyance.

Maybe, especially as they're so easy to work on, I'd be tempted to de-twang. But then, having said that, I own several HWs that I've never touched internally, so I know where you're coming from. One of them being my super-accurate .177 HW99. Only a slight twang, not too annoying and the shot cycle is lovely, so leaving alone for now.

And my '98 is very twangy. But I haven't used it in ages and it so accurate and forgiving as it is. Maybe a candidate for future fettle.