1.) I used to have 3.73's. I went back to stock 3.07's, due to Roe SC installations plans

Too much additional HP for 3.73's and Michelin Pilots, IMO.
2.) For now, my Viper is the same as it was with the 3.73's. The difference between 3.07's and 3.73's is noticable. My car is a good bit slower with the stock 3.07's. I really miss the 3.73's. It is much slower out of the hole, and IMO a good bit slower to 60. Less noticable in 2nd-6th, but still seems slightly slower. Do I have hard proof? Nope. Do I have any reason to lie? Nope.
3.) The difference between 3.55's and 3.73's is going to be minimal. The shift points are only a couple MPH difference. Although, if you can modulate the clutch/gas, and get the tires to hook, I think the 3.73's would be better by a very, very small margin.
** I don't think gears are for everyone. If you don't like to shift frequently, stick with stock. If you have a hard time getting the tires to hook with stock gears, stick with stock. If you find the Viper difficult to drive or tiresome, stick with stock. If you drive, or like to know you can drive 170-194 MPH, keep the stock gears.
** If you find the Viper is a little bit of a dog out of the whole (0-25 MPH), you will like a gear change. If you have no problem getting the tires to hook on a launch (3.07s), gears may be for you. If you don't mind shifting more frequently, and prefer a car that is on the edge of traction/no traction, gears may be for you. If you want a more violent/head slamming ride, gears may be for you. If you don't mind a top speed limited to 168-175 (give or take), gear may be for you.
** I'm trying to get the best of both worlds by keeping the stock gear, and increasing HP/Torque. Of course, this is an expensive road to travel. Unless nitrous is a consideration.
Later