I plan to do 24h of le mans on Project cars 2 with friends on 12-13 july, it would be amazing if my Pimax was there for this event !
No chance. It will be at least mid June by the time Pimax even gets all the feedback from M1 reviewers and reviews it, then there's probably gonna be at least one thing they will fix then have to re-test, so lets say another month before its ready for production, then theres the production line tool-up/startup/quality fix time to get to where high quality production units are even being made. Just going on what Pimax have already said: the first month they will only make 100 units and slowly ramp up production numbers every month, then there's a 10 days or so of just shipping/getting through customs time. Even if you have a single digit backer number, its probably realistically gonna be September earliest before its in your hands.
I think Pimax said in their same update post that their full production speed would be like 500 units a month UPDATE: WEEK not month (thanks Ch4rli3_G0rd0n), which if true, and your backer number is worst case somewhere near the last, say 6000, that means your unit is only going to get made 4 months after production start, then add in shipping, which means best guess it will be in your hands mid January 2019.