It is IMPOSSIBLE to predict cluth life. Anyone that gives you a number is nuts.
I changed my disc at 98k and there was 40% material left. I drive very fast, BUT I never abuse the clutch. It is actuall really simple: never let the clutch slip- you open the driveline, shift, close it. Never allow the two to slip (except starting from a stop of course). Never spin the rear wheels. (why would you anyway?)
Most drivers dont know what cliutch abuse IS.
But in the thousands of E39M5 posts Ive read, many will blow through stock clutches in 20k miles... (this is the 20-30 yo crowd who learned to driver on automatics and things The fast and furious is a driving skills primer)
And know that you can destroy a cluitch on a test drive.
Keep it as simple as possible...but no simpler.