I don't know much about the M20s so I can't help you there.
Yes, if you are OBDI you just plop a chip in your factory computer. Easy as that. You'll want gauges to monitor things to make sure the tune is pretty close. As far as tuning you have many options.
Dunno about books, but I am looking to get into tuning sooner rather than later and I need to start reading up myself. Thanks!