15 years ago I was flying an S-76 at 145kt with a 30-kt tailwind (groundspeed 175kt) when I flew into a Southerly Buster making its way up the coast at 40kt. It was like hitting a brick wall, airspeed leapt to 180kt, 25kt above Vne, and we zoomed up in the sky, even as I lowered the lever and slowed down.
No bad flying effects were displayed by the machine, and an email to Nick confirmed that this would have no effect on the aircraft at all - thanks Nick!