I think your speed isn't as important as your RPMs. I have 700 miles on mine, and I'm still driving around like a grandpa, for the most part. Occasionally I'll step into it a bit and get the RPMs up to around 3, but I haven't yet gone over that.
When I drove it home from the dealership, I was driving between 65 - 75 MPH on the highway, but my RPMs were only hanging around the 2 mark. So the engine wasn't working too hard.
I agree that it's important to drive at different speeds. So don't use your cruise control for a while.
I plan to keep my original oil in for 3,000 miles, dump it and start with Mobil1 (probably). It'll be weird because I've always used Valvoline, but I've heard lots of good comments about Mobil1.