Splash, you seem to be over-motivated here
I have watched leica M cameras on eBay for a while and while 299€ is in the low-side - the auction has not completed yet. Also M2 like this tend to sell for anywhere between 350 and 550.
The auction you have linked offers a 1 month warranty - enough time to see whether the camera works or whether in needs a CLA.
So - if you want one - go ahead