Complex sentence: They all used the same basic ultra-compact aluminum alloy chassis (except for the MX, which had a different chassis, but used similar styling), but with differing feature levels, internal electronics, and external controls and cosmetics.
Split into simpler sentences: They all used the same basic ultra-compact aluminium alloy chassis (except for the MX, which had a different chassis but used similar styling). They differed in feature levels, internal electronics, and external controls and cosmetics.