Naz,
can't say about saving for home, cause I don't know your financial situation and this is car forums not CPA forums.

I wouldn't buy BMWxi non SUV, I own 335xi coupe so I am qualified to say that. The suspension is not sport even with sport package (it sits high), no stagerred tires setup. if you can wait for F30 M3 or the coupe version of it. from what I read it'll behave more for daily driving being 3-turbos, high torque and still rev high if you want.

As far as lease, make sure put down 7-month safety deposit to lower money factor. and if you total the car during lease time you got all deposit backs, not like down-payment.
Also I think BMW has up to $3500 holiday events right now.

At last all x35 model engine by BMW is no longer N54 (unless it's 335is or Z4), they are now N55 seems to be more reliable albeit less tuneable; but hey you lease so who cares if engine will die after waranty (can't lease pass waranty).