Answer: The original GR80 headphones for a time were supplied with the 'L' type cushion (hole in the centre) part number 'GR0120', whereas the current models use the 'S' type cushion (no hole) 'GR0115'.
Answer: The GS2000E and PS2000e are available in a 4-pin XLR balanced cable versions, but they are special order items that have to be custom made. If you place an order through any Grado dealer, we will be able to order them in for you.
Answer: At September 2021, the current Grado SR60e/SR80e/SR125e replacement ear cushion will fit the original SR60. https://www.grado.co.uk/accessories/grado-sr60e-sr80e-sr125e-cushions.html