1)Make sure your choke is completely off and the choke plate has some tension holding it open, not flopping. Sounds like your fast idle cam is engaging.

2)Yes, that's most likely your problem. Install a ground between the engine and the body or from the ground cable to the body.

3)Get the front end checked out by an alignment shop. Most likely a wear issue.

My car is dead stable up to 150 mph (indicated) with the fast ratio box (no boat feeling here!) but I've gone through all the suspension, good shocks, big front and rear sway bars. No front spoiler so lots of nose lift at high speed but no wandering.