I think the stiff ride is very subjective.
I don't think it's a stiff ride at all, but we are used to sports cars.
Recently I had an M2 and Mrs a Mini JCW - and the X1 30e feels like a Bentley compared to those.
We have got the 20" alloys and I personally find the chassis very good. Maybe it's people comparing to other SUV's who find it harsh?
I find the standard seats really good. Would not want/need any additional support with the electric adjustable seats.
I would defo spec memory seats if more than one person drives it.
We didn't get full parking surround view, but wish we had it.
Great car....sounds ideal for you. Get it