Where is your sig?
That sub box probably weighs 40 lbs, the spare and jack another 40-50. I did a lot to my car to get it down to 2750 lbs.
You can weigh you car for free at the public works bldg on Rochester rd around 17 mile. If you want to take your car there I can show you where it's at. I go there every time I take weight out.
Milan is pretty tough for traction too. Ubly is the best in my opinion. Lapeer is ok, but sometimes it's pretty slippery.