I'll echo others: spend your money on gears and converter first. Cam and intake and exhaust can all be 'right' and make good power, but the wrong TC will make you hate driving it. A mildly warmed over engine will feel 10x better with a better TC, whereas a stock TC with a huge cam and badass heads will still drive like a turd.
Definitely upgrade your transmission cooling too.
3.23-3.55 is about as big as I'd go for something that sees lots of street miles. I have 3.91s in my dart, and when I was in Vegas it was a chore to drive from Summerlin on down to my shop (which was near the Ikea). It wasn't awful, but with dronemasters (flowmaster 40s, came with the car) it would grate on the ears a bit. I was always glad to get to my exit, and that was the longest freeway drive I'd ever make with the car too..
Think of a modern high-stall converter like this: the name of the game is number of firing events you can pack into the amount of time you have to complete your task. Whatever that task is (fun, burning rubber, 1/4 mile, etc). The more firing events, the more work done by the engine, the more fun/speed/power you pack into that timeframe. If you have a low-stall 2000rpm converter, then switch to a higher stall 4000 rpm converter then you'll be getting almost 2x the number of firing events (it's not that simple, actually, but for the sake of discussion let's put that aside). That 2x number of firing events, happening at a rev-range that's already making more power means that you see a SIGNIFICANT return. The difference between similar cams 1-2 steps apart might be 15-40hp. Which you'll notice, but not enough for the wife to understand the investment. Swap the TC and she'll get it. She may not like it, but it will be a very obvious difference. Even a stocker with headers will start to feel mighty impressive with a performance converter. Modern ones are also much better at their job than old ones, and won't have the disadvantages many claim come with higher stall.
Because of the complexity and variables involved with a converter, don't buy one off the shelf or based on price. Call a couple places and give them a very in-depth idea of what you want and they'll deliver. Don't let them talk you into a race piece and if they stay fixated on race when you want to talk street - go to another source. Folks here can suggest good companies to deal with. Weigh your car and if at all possible try to get some idea of how much power/torque it makes (dyno run, back-road top-speed over a set distance, etc).
A good shift kit will ensure that the transmission does its thing when and how you want it to in order to keep you from trying to operate 'off peak'.
