Mine are carbon and have the grooves (and killers) as well. As I understand it, you can buy either the Ti or CF cans with or without the db killers.

I think not all of them came with the ability to use the inserts. If yours can, a machine shop could make some for you. I could give you the dimensions if you want.

Be aware that if you lower the bike it can make it difficult to get it up on the centerstand. The comfort seat definitely affects how easily you can reach the ground. The more slippery and narrower stock seat makes it easier.

Besides all the other comments above, I would not recommend the gel seat. The reasoning is that it is a bit wider and stickier at the front, making it more difficult to reach the ground for those with shorter inseams. I personnally have no problems with the stock seat. It is quite wide at the back ...