So, have you been able to get it fixed yet?
I had the same problem with my 15 RS. All the gears seemed notchy from day one, but not every day. After a while it became every day, and harder to shift into 6th gear.
A couple of weeks ago on multiple occasions it just plain would not go into 6th. Took it in for a service and told the tech about the shifting problem. Got a call the very next day that they were ABSOLUTELY able to replicate the problem.
After 3 weeks and one damaged-in-transport replacement tranny, it now has a whole new correctly-functioning transmission.
Shifts like butter (so far)! Feels a lot stronger than the old one, and seems like the ratios must be different. Car feels much peppier now.
Just glad it's still under warranty. I have had so many dumb little problems and so much warranty work with this car (and one other major one that still is not fixed) I'm starting to think this car is jinxed. It's only a year old!
The morning after I got it back from the dealership, a rock hit the driver's side of the windshield and I now have a foot-long crack across my line of vision. Can't freakin' win!