Sorry to hear you're bailing on the 135/3.4 Jaap. I just got a black OTZFO universal short focus mount for the lens head on my 135/4 and tried it on my 20D with the 14167 and R-EOS...definitely a "digital-ready" lens. Can't see any reason why it shouldn't perform as aptly on the M8 as it does on the 20D (exit pupil has to be the same distance from the sensor to focus on infinity). Nice thing is the lens cost me $265 last year. You might look around for one, from all accounts it's 98% APO 😀
But I sympathize with the syndrome although my GAS-tank is restricted by a rather meager budget 😀 Right now I'm debating selling my 43mm-style 50 Lux for a cosmetically-challenged but glass-perfect 46mm one...going over and over in my head if the closer and shorter-throw focusing, common filters, and ability to be "coded" outweighs the useless pull-out hood and probably $500 needed to buy up.