Which tuner to get?
HP Tuners and EFI Live are the main products out right now (PC Based)... best bet is to visit each site and see which you think fits your needs
There's also Tunercat and LS1 Edit, but neither is very highly reccomended anymore
W/HPT, the credits allow you to do various things... example you could tune 4 vin locked LS1 based vehicles... or 1 unlimited year/model and 1 VIN locked, or 2 LS2 based vehicles (VIN locked) ... or you could tune your car, upgrade to a custom OS, and still have credits left to use towards additional licenses
The credits are just a method of licensing , http://www.hptuners.com/order.php has all the various costs (how many credits required to apply that type of licensing for that vehicle)
http://www.hptuners.com/credit_faq.html provides more examples
Thanks!

