A CM chassis is stronger even with the lighter wall tubing..
its much stiffer... myself I wont even build a MS chassis.. I
quit building chassis's 2 years ago but when I was I wouldnt
even build a MS... every one wants a light chassis and CM is
a easy way to save weight.. it would be a CM chassis, strut front
and 4 link with a anti roll bar... you pay for tubing by weight,
there is a cost difference for CM vs MS but you are paying for a
.083 wall vs .135.. that extra wall thickness adds up quick... if
your building it yourself you will have about $1200 in tubing
EDIT
The biggest cost difference between the 2 is the welding... CM
has to be tig welded... that takes way more time.. time is money