You should check out the National Harley Truck Owner's Club. I'm not sure what their URL is, but they have a forum at www.nloc.net.

For mods there is a lot of info in previous posts about them, and even more in the NLOC forums. They used to say you couldn't run a pulley without a chip, but there are many people now that prefer the stock program with a pulley because it has a safer air fuel ratio and timing curve. It seems like most people get more gain from a chip with no pulley than they do with a pulley and no chip.

For suspension stuff check out the RUSlow performance section on NLOC. I'm going to buy some QA1's from Stan in a month or two. That is the route I would go, especially if lowering is in the plans. The QA1's are adjustable and rebuildable. They are more expensive initially, but probably cheaper in the long run