EFI Source makes a complete plug and play ECU and harness setup for both early and late Gen 3 Hemi engines. No drive by wire option.

If you want to use an MS3Pro ECU you have to either make your own harness using their un-terminated harness, re-pin an EFI source harness to the MS3Pro ECU, or re-pin a factory harness and make it a standalone harness. No drive by wire option.

EFI source makes an adaptor plate so you can bolt on any cable drive GM LS style throttle body to the factory intakes. FAST makes bolt on cable driven throttle bodies for factory intakes with the correct GM TPS and IAC sensors that mate up with the EFI source harness.

If you want to have drive by wire going with a Holley Dominator ECU and Holley harnesses is the way to go.

You can also go the drive by cable route with Holley as well using the Dominator or HP ECU and their harnesses.