I suffer with lower back problems - and driving over 25k miles per year, I was very worried about what to get... I was even going down the Volvo route, to be sure to get a comfortable ride.
All the Q3's I saw before purchasehad the Sports seats fitted, but I wanted to know what the standardseats were like (without lumbar adjustment), and I didn't know whether I would need to budget for better seats.
I have to say, I've not had a moments issue with the SE ride and handling on Standard wheels- It just devours distance comfortably, and the seats, even in standard fit, are comfortable - I've done 500 motorway miles in a day without problems, and a daily commute of 50 cross-country miles is totally fuss-free.
A lot of the reviews I read, said choose SE for comfort, and don't bother with the adaptive dampers given the price - but, as reilsab says, it's each to their own preference.
However - £900 can buy you a lot of other goodies that you'd use more often!