Got my Ixils about 2 or 3 weeks ago but have not had the time to put them together (I'm a full time grad student)
Finally put them on today -- easy job -- went together slicker than cat**** on a linoleum floor
Goes in for the TOR tune on Thurs.
It is 30 Celsius in Calgary today and I went for a 2 hour ride this afternoon -- lots less heat coming from under the seat without a doubt

-- which is one of the big reasons I changed them.
Sounds great and definitely less back pressure - found myself having to brake where I would have used engine back pressure before.
I also took off and silicone-ed down the windscreen to stop the annoying vibrations it makes.