The 04' was another new begining of too much B.S. bolted to the engine, and more sensors.. Personally, I do not like the ceramic lifters.. If the ASET is a CEGR ( cooled e.g.r.) then you will give your wallet a 'workout' The exhaust system at the engine is very expensive and the EGR valves dont last very long, and at a grand a piece.... well.... you get it.. heck the EGR crossover pipe with the 2 sensors in it is $1700.00.. and on back order at times, and forget replacing the cracked exhaust manifold center section... The MP's.. Strong engines. but many exh. repairs will be done. I keep saying it's expensive.. all repairs are expensive, but the frequency of some of these repairs 'chap's my a$$'... When I was working in the Mack dealer a few years ago, I would cringe, on behalf of the customer who was trying to keep his truck on the road, when he got a bill for $5000.00 - $8000.00 for exhaust system repair, and then have to bring it back because the MILF light came back on... OK,,, time for other opinions.. jojo