I know the oil change interval on my '06 RSX is 10K miles and even my '90 Integra was recommending 7500 miles.
As far as the Mobil 1 thing goes, I've been running it in the last few cars that my dad and I have owned with no problems. Heck, the Integra was still getting factory gas milage (approx 24 mpg) when it had 170K+ on the clock.
The RSX has been on a steady diet of M1 Extended Performance ever since its first oil change and manages to get a few (2-3) more MPG than factory, even with a few bolt-on's.