I agree completely with 1911 and FJDave. Solid advise. I've changed all the fluids (except) the ATF to synthetics and just recently at ~17,500 I changed the air filter because I often drive in dusty conditions and had a new one sitting in the garage. I was surprised how dirty it already was (not terrible but it was doing it's job) and noticed that the engine sounds a little less 'labored' on my normal routes. Must be breathing a little easier. Mine's an '07 but I added the Cyclone Pre-Filter as well in the last few months for the reasons I stated above. I also use synthetic grease on on the lube points.