As has been mentioned, if you're really going in for 7 years then leasing will be throwing money away. Even if you lease with the intention of buying it out you'll dump a couple thousand more into it than if you had bought it initially. This is especially true in states that levy a tax premium on leases (like PA) which bumps from the normal 6% sales tax to 9%. If you're the type that is horribly fearful of post-warranty repairs, then you should either purchase a dealer sponsored extended warranty or just stick to leasing.
Regarding ED, I just did this on the 335i that I'm leasing. The upside is that you have a nice low cap cost which has a positive effect on your monthly. The downside is that there's a 3 point adder on the money factor which can bring it back up a tad. BUT, that adder technically is to offset the fact that BMW picks up your second payment since your car will likely still be in transit.
You negotiate your ED deal just as you would a local purchase. One item of note, the ED invoice only applies to the BASE model price. The options are not discounted.
If you're already traveling to Europe, then there's a far greater benefit to be had than for individuals that are going specifically to get the car. In my most recent case, the savings essentially covered airfare for the family. I reasoned that it was worth it to get a nice vacation in Europe for just the cost of lodging and meals. Plus it's an absolutely awesome experience as Yobyot indicated. The waiting does suck, but it just extends the Joy.