@nakaimoto
Congrats. You will enjoy the "R" for sure. The light Marchesini forged wheels do make a big difference.
As for the seat, I didn't have a complaint about the stock seat knowing it's "sporty hard". I got used to it and it became a non issue.
However, my buddies wanted to take longer rides where I felt than some extra padding was necessary.
My other bike was a Panigale where it was not an improvement in comfort.
That's why I bought the comfort seat for the Monster.
The comfort seat is well...much more comfortable albeit still firm and a bit taller.
I have now traded the Panigale for a Multistrada.
Had I owned the Multi at that time, I would not have bought the comfort seat.
The bottom line for me:
If you only have one bike then yes, buy it if you feel you need extra padding.
However, if you have a more comfortable bike for day trips then it's not worth it.
As for the exhaust, whichever you choose, do get your ECU flashed or buy a Rapidbike unit regardless of any manufacturer's claim that you don't need it.
You will lose torque guaranteed, because of a lean running engine.