Well I guess it's pretty much covered by BV and Jenks.
I guess the difference between the Sierra diff and MX5 is the Sierra doesn't have arms sticking out both sides making any torque movement worse. Sodily mounting the front nose of the diff will only cause metal fatigue and fracture of the chassis sometime in the future. Mazda realised this and fitted a PPF as standard. Triangulation of the chassis will only make things worse resulting in a weld faiure along the HAZ of a weld.
I spoke to Nathan Sunday and the only reason the diff broke was because he forgot to fit the diff washers....LOL..
Ok he agrees the diff mounting below the diff wasn't upto the job but this didn't brake.
Basically if the front nose of the diff was to be solidy mounted as per Westfieid and others who grow onions then Mazda could have saved a lot of RD money.
Well just my thoughts I guess others will disagree........
But I look at it this way, if Mazda fitted it it's good enough for me...
Johno