You're going to find very limited options for the e70 right now. This may improve over time, but it's just going to be a waiting game to see who develops anything for the X5.
H&R and Eibach have springs, but there are no aftermarket shocks available for the e70. Until Koni or Bilstein makes one, there's little chance that Dinan will have one, since they don't make their own. No one makes sway bars as well, again you'll just have to wait and see if any company will make those as well.
Sorry to say, but if you wanted better handling, you should have ordered the sport package.