All OP wanted to know is whether he should give the M3 to his daughter. Consensus on the forum is that its a bad idea (love it how people sidetrack a topic on this forum).
OP-If you could afford it-would suggest keeping both. If not-sell.
2011 Alpine White/Fox Red E90 M3. Sunroof Delete/DCT/No power seats/Square Apex ARC8s+ PSS /ACM Exhaust Mod+ EAS Tips