My 325i is a Sep 05 build, and I had the mid 2007 software put on it when I was having mobile phone/bluetooth problems - car seemed better, and from memory some usability tweaks to Business Navi system - but not bringing the ability to show maps like the updated Business Navi (when they put those "bookmark" keys in...
Most weird change was the navi saying "take the xth turning on the left at the roundabout" rather than "take the xth exit on the left at the roundabout", but the Lady Penelope voice is still as polite as ever
Adelaide Motors were quoting about $250 to do a software update, unless I could establish that it was a warranty issue.
After reading the link to the version 33 software, I may be interested - I have never been completely happy with the take-off...