Here's my experience with the M12 stubby.......
It has no problems removing lug nuts on my Saturn, aluminum wheels, torqued to 103ft/lbs. It has removed the crank bolt from it as well which was torqued to 162ft/lbs and it has removed all the subframe bolts which were torqued to 155ft/lbs. All without issue. It has also removed the axle nuts from the same Saturn which were torqued to 166ft/lbs and that was with a 3/8 to 1/2 adapter so I could use a 32mm socket. My car has been a northeast Ohio car its entire life. Plenty of exposure to salt, snow and rain. I've always used an XC6.0 pack with it. There have been a few times where I've needed to use my M18 2767, but it's been few and far between. I highly recommend that 3/8 stubby to anyone, but definitely use an XC pack, it will make a difference.
Now, with all that said, I am so incredibly temped to pickup one of those kits the XC HO 5.0 packs. That's such a damn good price and the nearby HD has two of them sitting on the shelf. So tempting.