The fourth-gen RAV4 is nearly identical in size to its immediate predecessor, so the major changes pertain to its general layout and driveline configurations. The burly 3.5-liter V-6 engine is history; it arrived with the third generation and was instrumental in the RAV4 winning two of our comparison tests (once in 2008 and again in 2010). A port-injected 2.5-liter four-cylinder now is the sole power source, aided by a new six-speed automatic transmission. (Last year the base four-cylinder was p