First off, nice choice with the options. Love Santorini (though I was too cheap to order Individual paint myself) and I love my speed cloth too.
#1: Can't really answer this as I ordered mine a year ago, but my response to #3 should help answer this one.
#2: My trip (see thread here
http://www.m3post.com/forums/showthread.php?t=733294) was 18 days and cost $2700 without flights. I kept an eye on the budget but still splurged on a few things here and there - the fuel bill for one
#3: Absolutely. If you've never driven in Germany it's a real treat, and that's before you factor in the unlimited speed sections. Alpine passes are spectacular and I would suggest working some into your itinerary. Food and beer are excellent.
My route was roughly Munich > Stelvio > Milan > Zurich > Heidelberg > Frankfurt > Munich and there was plenty to see and do in the 15 days or so we were on the road. Depends on your priorities but my suggestion is to take back roads that are often less busy, provide great scenery, and also provide a better feel of the area instead of rushing by it on the highway. We found there's less English spoken on back roads compared to populated areas, but that's part of the fun
If you can make ED work, do it! You will not regret it.