You mensioned that when you come to a stop, the engine spins freely for a second, like you put it in neutral. Then it just 'catches', BANG - off you go like normal. Usually happens when the engine is cold. Once warmed up for a few minutes, it's fine.
I had this same problem for a few weeks when I first got my car. A nice change of fluid (the 4 quart drain & fill method three weekends in a row) has fixed it. Been fine for over a year now.
Another thing that will help, get an external tranny cooler installed to suppliment your stock transmission cooling. All of my cars with a tranny cooler have NEVER suffered a failure. $100 or whatever it costs for the parts & install is worth it.
Eventually, you'll want to install the CD4Ejr shift kit from Trans-Go. I'm working on installing mine soon. I'm a DIY kinda guy. Tranny work is always exciting, you always think you're gonna ruin it.