If you use the manual +/- transmission that comes with the automatic trnsmission, and let the car slow down without downshifting, the car does it itself. However when it gets to 1st gear it looks like the car jerks or stalls, like a real manual, transmission. Is that normal?

 

i believe that is normal, I never put the +/- into first when downshifting if i ever do. 2nd gear is fine. The only reason you should be in first gear is if you are completely stopped b/c first gear is your torque gear that will get you rolling. It's meant to be a quick gear just for that reason.