Read up on Sentra.net. It's a great site and believe me, you'll have your hands full with information. If you need more sites just let me know, but I guarantee you it'll be a while til you get done with those pages. It's definately GA16DE if it's a 4-spd, but can't really tell what model. At least I can't. Somebody on here could tell if you posted interior pics though. That always gives it away. Have fun!