I pretty sure Aluminum is a better conductor, but it corrodes faster, much faster than brass, copper. Thats why they used Aluminum wiring in some houses then stopped. It was better and cheaper than copper, but then they learned that it corroded way too fast and ended up with a lot of house fires due to the corrosion, so People/Contractors had to stop using it.

87 Toyota 4Runner-RV Head, Custom Grind Cam, Doug Thorley Header, Keith Black Pistions, 2 1/4" Magnaflow cat, Dynomax Exhaust
2003 Toyota Matrix XRS-Injen CAI