running steel diifs will make you overweight. I run lightened steel diffs and I still come in heavy for mod class.
for diffs just as strong but lighter I run Hardcore Alumium diffs. you might have to work on the cases a little but it's well worth it.
yes you can twist the chassis with the 3mm top deck. but the forces implied on the chassi/top deck when your racing are no where near the pressure you are using to twist the chassis. even in mod/foams/carpet. I have found that a modded tub TC3 will take a tweak with a moderate hit. so far we haven't had a tweak problem with the B.M.I. chassis with either top plate on carpet. we mostly run stock and some mod (7x1)s we will run the 3mm top plate on med to high bite tracks.
if you have any other questions please e mail me at TimXLB@hotmail.com
as for being wimps..I never wear a coat all winter long. last night it was 1 above with a wind chill around -40* F
also I'm a transplanted Canadian..... so I know about winters.
Thanks for posting you thoughts on the B.M.I. chassis I am looking forward to running ours on carpet soon......as soon as I get a weekend off work.
What body were you running??? track size??? Etc??