EFI Performance LLC is a late-model GM, Ford, and Chrysler dyno tuning and performance automotive specialty shop.

February, 2017 - We have added a line of pigtails and adapter harnesses to products; check them out!

May, 2016 - Mail Order Tuning has been moved over here from TunedbyFrost.com but can be purchased through either site. We hope to have our product listing updated within the next few weeks. Thanks for reading.




Mail Order tuning for ALL 97/LS1 - 2014 GM V8 Cars and Trucks with BOLT ON MODS 4L60e, 4L65e, 4L70e to 4l80e conversion harness 95 - 97 LT1 Vented Optispark harness