so you are the one who has been selling the B4 top shaft for the mid on ebay. i made one about 6 months back too but mine is one piece. I see you are using MPP LAZER arms, same one i am using. Unfortunately these arms seem to flex noticably. However they should not be easy to break. so far mine holds up fine. i am however getting fed up with the Mid as i always seem to find sand in the gearbox no matter how hard i try to seal the drive train. i run on extremely dusty and sandy tracks so the sand is very fine. However the good thing about the mid is with the use of the aluminium chassis, its practically unbreakable. i have thought of going to my Lazer ZX but i think in few weeks i will probably snap the graphite chassis. i will re seal the drive train one more time and re try again. I just found out that the pargu2000 alloy center gear i installed 8 months back is now chewed up thanks to the sand in the gearbox.. bummer.
oh yes, do read my blog on the optima mid and what changes i put the car through..
http://superturbooptimamidspecialzx-5.blogspot.com/