Does it have to be a BMW? If you want a reliable estate for the wife then I would look to something like an outback or legacy estate? Tried to get my wife into a legacy estate last year and she thought no, too big, so ended up with an E46 316 M-Sport. Had loads of issues so it went on a scrappage deal a few months back. Nothing major went, but enough to annoy, especially when it is her car. I totally regret not pushing her into that legacy and installing a reversing camera or something like that. It had a nice spec too, leather, big sunroof, etc. Now resale on one maybe a different story to a 520d M-Sport.