I purchased the returnless kit, which is no longer offered. I installed the system, which was pretty easily. The car would not start, after calling tech support through Edelbrock and buying a ignition box, because a stock HEI modual doesn't emit a strong enough signal that the ECU could pick up. It would have been nice if that was mentioned in their instructions, as I did read them completely before installing. The system finaly seemed to work, after driving the car for a couple of weeks I started having problems with the electric fan outputs causing my relay to click on and off at a annoying rate (every second or two). I checked all wiring and tried differn't relays, to no avail. The tech support always took my information telling me that the problem was weird, and they would have their engineers call me back on two seprate occasions, but they never did. The other problem I had was fuel pressure fluctuations while I would drive it, errors would constantly pop up (FUEL PSI HI) (Fuel PSI LOW). Tech support offered to sell me another fuel system which is really ludicrous, considering I paid a lot of money for a system that they discontinued (returnless). When the system was working throttle response was awsome, along with power, but this system obviously has many issues, fuel economy was adversly effected. The included tablet is very cheap looking and seems to be from china. I wish I could return it, I guess I will call tech support again and see if they will fix these problems.