I was running Stage II for about over a year, and sadly, I forgot to put the mileage at of the install. I'm sure I can dig through old invoices and find that. Probably around 20-30,000 kms.
Most vendors allow for 'low torque' tunes, to preserve your clutch if you ask them. I was running a 'low torque' recommendation from BM on my JB1. It was running fine until I decided to upgrade my clutch, and my wife learning standard put the nail in the coffin on that clutch...
Went with the Ringer Racer clutch (~$600 and good for 575 lbs-ft) /w OEM Flywheel (~$250 off the forum), cranked up the boost and with the money saved on the SMF options, threw in a Wavetrac. Spent extra on the thrust bearing 'fix'. Absolutely love the set-up and it feels like stock. How long will this clutch last? Time will tell, got it installed in January.