What are the limits while I'm breaking my car in?

Is it broken in after 1000 miles or 1200 miles?
Am I not supposed to go over a certain RPM? Like 4,000 RPMs?
Should I be going under 65mph or under 80mph?

I've heard various answers from different people...

 

According to the manual, 2000 km or 1200 miles (i think it is?). Under 4,000 rpm. No cruise control, try to vary speeds.
The manual didn't recommend an oil change after break in. My previous Lexus recommended this though.

IMO just follow manual recommendations

 

So I can go as fast as I want as long as it's under 4k RPMs? This would mean that there's no greater amount of stress on the engine at 3500 RPMs in 4th gear than 3500 RPMs in 3rd gear?

 

80mph is the fastest you can go under 4k RPM.
Varying speed is the most important factor in breaking in your car.
I didn't change my oil till about 3,500 miles.

Do a search on the forum about breaking in... there's plenty of info.