"- Having said that - make sure you do vary the speed of the engine - if it is wearing a groove into a seal you'll accelerate that by driving at a steady speed. "
This is an urban myth. Trust me; I worked in the service department at a BMW dealership for 3 years. I know what’s bunk and what’s not, and what the dealers tell you to do but you don’t need to do, it’s just for them to make extra money off of you.
What I listed before is standard operating procedure for all new BMWs. If you think the TSX is made so well that it doesn’t need to be broken in, in the same manner, I’m afraid you are wrong.
Like I said, you really should change the oil after the first 1000K miles. After that you are good for every 5K miles between changes. In fact, if you don’t race your car, and use full synthetic you only need to change the oil every 7500 miles. Just don’t cheap out on the oil filter, that’s a nono.