As I understand it the courts have ruled that the software loaded into automotive ECUs is public domain. As of right now a tuner program cost about $600 and requires "credits" to alter the tune in a ECU. The tuner program has a very steep learning curve and of course is not as good as a dyno tune. When using an LS style engine there is the problem of wiring and ECU reprogramming. Plenty of info on line how to alter the stock wiring but must send the ECU off to have it programed which is between $100-$200. Plenty of aftermarket packages to run a fuel injected engine but the problem is not all will also run an electronic transmission. Range of aftermarket "kits" range from under $100 to over $2000. As Ed mentioned the popularity of the LS based engine is so big this is a quickly changing subject.