Sounds like you're on the right track with this build. I agree with Royce almost completely. Dual plane is going to be the way to go if you are truely interested in torque. A mild stall as royce suggested is also a pretty perfect compliment. I would also suggest a smaller cam if you're interested in a torquey ride, and those heads you speced will work well 268 split duration comps would work with them, check it out. I don't think you need Pro 1's or AFR's for this build.
Your 3.08 gear may work well for this build, but I'm almost positive this is an open unit. If you are going to have a slight stall and a motor that's building torque quickly, I really think its in your best interest to scrap this open unit. When you make the change I wouldn't step up past 3.23's or 3.42's. Your car is light and your motor is going to make plenty of torque, not to mention they'd be great gears to use in a driver (considering I'm sure it will be on the highway from time to time).
Royce, perhaps AFR heads aren't the best flowing heads out there, but they do fulfill a couple of valuable criteria. First off, they come ported, which is a big plus. They only cost about 100 dollars more than an unported set of Pro-1 heads and top out at flow numbers that are on average (using memory here...) about 30 cfm higher. Dart heads tend to be pretty meaty, so I'm sure your port job is excellent (judging from the quality of the rest of your build!). But for a guy who very probably is doing his first build, wants the best bang for his buck and doesn't want to pay 600 dollars for a pro port job and doesn't have a clue how to do it himself, AFR's are great heads! I totally agree with you when you say there's more to a set of heads than numbers, and that's why the AFR's are good. They've proven that they have good turbulence, great velocity and good top end flow. For a guy like you, Royce, I'm sure they seem a little cheesy, and we all know who they're marketed to (bolt-on wizards, which is pretty much what I am so far). For guys like you who can do a great port job, know exactly what they want and how to get it from their heads, they're not that wonderful. But if you're in the market for an aluminum set of heads and want the biggest bang for your buck from an out of box set of heads, AFR's are pretty much unbeatable. I guess what I mean is, Darts adn AFR's are kinda like apples and oranges. Maybe thats what you meant anyway-
K