Game changing kit.....
What would be your list of components, that over the years (up to the present), has genuinely moved the goalposts for its level of performance / innovation.
To get the ball rolling, here is what has come off the top of my head:
Leak Troughline Tuner
Naim NAT 01 Tuner
Rega Planar 3
Leak Stereo 20
Celestion SL6 (first metal tweeter)