I just got my seat recovered on the '98 B12. After 54k miles the vinyl started to split at the point towards the tank.
The upholsterer installed a gel pad for another $60. The seat weighs about twice what it did before.
I've ridden it for about 200 miles and have to say I should've had this done when the bike was new. I rate this with stainless brake lines as got to do on every bike.