uh, read the next line down in your engineer's handbook. find that line that lists the density of the material. steel is much more dense then aluminum, thus HEAVIER when comparing say a bar of steel that is 6 inches long and 1/2 inch diameter and a bar of aluminum with the same dimesions. with aluminum, they can make the bar thicker, thus overcoming the lower strength. remember, it is not only the strength of the material, but also the cross-section area of the part that determines strength. to acheive the same strength in a steel strut bar that an aluminum strut bar achieves would require about 20lbs of steel or so. now how do you think they get any stregth at all out of that 1/8 in hollow steel tube and brackets?????????????????
and uh, saab, porsche, bmw, mercedes, ferrari, lamborghini, and many other high end car manufacturers all use aluminum control arms. panoz makes a whole car chassis out of aluminum. f1 uses carbon fiber to make their control arms, and HELLO your WHEELS are made out of an aluminum composite. excuse the sarcasm please, no flame intended.