For gas power, the 72" Extra is set up for the DLE-30 engine, and includes a firewall-drilling template for that engine and uses the standoffs included with the latest version of the DLE-30 engine. If you are not using a DLE-30, you will have to supply the correct length standoffs and drill your firewall accordingly for your particular engine.
We recommend the DLE-30 Rear-Carb engine for this aircraft, with a 20x6 (or Vess 19A or 20A) prop.
The 72" Extra includes a generic fuel tank, but the American-made Fortitude Fuel Tank is the best in the world and is a highly recommended upgrade.