I installed one a couple of weeks ago. Take your time, follow the instructions. Not very hard. Big comfort improvement.Thanks all for the information it was a big help,I did fit one to my GL1800 but I didn't have to remove the seat cover and the foam.
Bit apprehensive about doing all that because the bike has is still under the manufacturers warranty.
But will it affect my warranty on the bike.I installed one a couple of weeks ago. Take your time, follow the instructions. Not very hard. Big comfort improvement.