That's both awesome and reassuring to hear that you've had almost no issues up to 100K miles! Since those are very easy highway miles you're putting on it, 200K should be a cinch. I hope to have the same result as my mileage is mostly highway as well. I think I'm going to change my oil every 7500 out of fear of the potential issues with the valve stem seals, though..
2008 550i Sport-a.k.a. Hot Kraut Garbage
2006 Corvette Conv, Z51,6sp (wife)
2007 Honda CBR1000RR Sold
2005 Triumph Daytona 650 (wife) Sold