If you want to do your own tuning--which isn't rocket science, but does mean you need to have a clear understanding of how engines and engine control systems work--then the Sniper Special Forces package is a great place to start.
You can
get it for $320 here, and upgrade to their Commando package down the road.
The Sniper SF allows much more control of things than any handheld and let's you tune two cars with the basic package, and as many as you like by buying additional "bullets" for $150 each (tune up your friend's cars). Here are some screen shots:
It also offers auto trans control for shift firmness and shift point modification by RPM or MPH. Their support is top-notch, and the user forum is active and well-supported as well.
Try it, you will like it...