memory seat buttons are on the drivers side door panel.. below the window sill but above the power window switches.
Yes, Premium fuel.
Other things to watch out for:
Vibration at high speed - caused by unbalanced tires, wheels, or the control arms (supposedly a first model year MY2009 problem but members were complaining about this through MY2011)
Vibration felt through the steering wheel when turning (ie parking lot) - I believe the fix was related to power steering hoses
there is also a fix available to replace the flat edge sun roof deflector for a tooth/combed one (like in the E90) to eliminate the buffeting when the sunroof is open.
Oh, and get APR ECU tune!
F25 X3 N20:
2010 B8 A4 2.0T quattro (current)/
2013 F25 X3 x28 N20 (babymobile)