Wilson I don't disagree at all...I'm one of several owners that have had two chassis failures and replacements...both failures being to the top chassis rail, not the vertical strut between the chassis rails. There may well have been more failures of this strut than I know of (I will happily phrase that as "of course there have been more than I am aware of") but the earlier failures seem to have been to the horizontal rails and the failures have been remarkably friendly in nature. By this I mean that a degree of vagueness has set in...a bit like a slow puncture on a road car rather than a full scale "Oh F*ck" moment like you would have had with a dodgy rose joint failure on a race car being driven in anger. The failures to the vertical tube may well be more likely to cause a catastrophic event but this is supposition. I know of at least four clearly different M3W chassis; 1. Pre-production with no cross-brace behind the engine (but ahead of the body) - don't think any production cars got this one, but I could easily be wrong. 2. Bolt-in cross brace behind the engine - straight brace across between the top rails with a rubber bush at each end - my first chassis, 2012 and into 2013. Very crackable. 3. Bolt-in cross brace behind the engine plus small gusset type stiffener plates and a different steel specification and wall thickness. 2013 and up to 2014. My second chassis and just as crackable. 4. Triangulated, welded in brace between the top rails behind the engine. Doesn't seem to crack on the horizontal rails but the vertical tube now has a question mark against it. This might be batch related (this is a guess...could be batch of tube, batch of welding wire, dodgy weld plant - too much current, too little current, wrong polarity, hungover welder...who knows, too many variables, too little information). This version also has the rubber mounted bevel box. 2014 onwards. Just read KBMOG's post I'll add "more than a question mark" and quite possibly much more. 5. Very like 4. but with the bevel box in a rigid mount. Very few about. My third and current(!) chassis! Probably only as a replacement chassis and for a short time...and probably not many of them made it into the wild. 6. Much the same as 4. but with additional brackets for the Euro 4, SUV ride height version.
Before getting a bit too "Nobody expects the Spanish Inquisition" I will add that Revolutions in Perth, my local dealer, have been very, very good at cutting through any dodgy information/possible porky pies etc. that may have arisen and I will stick with a degree of optimism regarding the future of MMC and its approach to these issues although my glass is becoming empty again and needs sorting out!
