Picked up a used Rallye seat for my GSA and to be honest an finding it fairly comfortable but could maybe benefit from a gel pad insert , think it might also end up with a bit of a colour change as well as the white sides look a bit chatty
I got mine from there with the air pad built in. It’s brilliant and easily adjustable on the move with a button on the seat side.
It’s like an air hawk external pad but it is fitted inside the seat. Saddlecraft sell the external pads as well.
When sat on the bike if you press and hold the button in, it deflates to your desired pressure. If you want to re-inflate, you raise your weight off the seat and press and hold the button. I’ve had them on 2 bikes now and it’s just brilliant and so easy to use.