Your first sentence, I have to disagree with. JoeKD may do things differently than you or I. But that's a long way from saying he does not know what he is talking about. JoeKD has helped me out on several occasions, once in finding a larger capacity oil filter, and several other times in info he was giving on other threads to other people. So, no, I do not accept your assertion that JoeKD does not know what he is talking about.
Your second sentence is a matter of personal preference. For the record, I had two 2.7-equipped Intrepids, both went to over 230K miles, and all they ever got was conventional Castrol 5W-30 @ 3K mile intervals. I was not even aware during that time frame that these engines had a sludge problem.
However, had they been my personal cars, and knowing the issues the 2.7 has with sludge, I would run Mobil 1 5W-30 and change oil and filter @ 3K miles. Expensive oil every few months is cheap insurance against the cost of a major rebuild or engine change, for most folks.
And, for the record, in my current personally-owned 3.5-equipped SXT I use Mobil 1 Extended Duration 5W-30 and I go the whole 15K miles on it. Different engine, different requirements. It gets a new filter every 5K miles because I use the Mobil 1 M-301 filter, a larger cap. filter. Which JoeKD told me about.
Sentence three: ok, I missed where JoeKD mentioned the 500-mile figure. Still, joe was trying to make a larger point, which I think you may have missed. Nice work on your math.
One final observation: you seem to be having a problem with people disagreeing with you. It seems to be provoking you into calling me "lame," saying ohers "don't know what they are talking about." Just because they do things a mite differently than you. Well, maybe you will be more mature when you turn 15 in a couple of years. It's abig world out there, sport, with all kinds of people doing all sorts of things differently than you. Get used to it.
Again, joekd has no idea what he is saying.
If you buy synthetic oil, go the whole 5k miles. Don't be like him and waste your money.
BTW, joekd didn't use math. He just said 500 miles. He did not work out a problem like I did.