IUI vs IVF for stage 2 endometriosis?

I'm afraid I disagree. I would do a few cycles of IUI first, but be sure to decide with your doctor how many you'll try before moving onto IVF. If your tubes are clear and the lap went well, and especially if you find that OPKs work well for you, this is by far the least invasive approach and for your body's sake (never mind your bank account's!) you should give it a go!