I'm running Rotella T Syn 5W-40 in my Speed. I'm on the 3rd change with it. I just got an analysis done by Blackstone labs after 5,000 miles with good results. They recommended going 6,500 miles on it. Rotella is full of additives and wear reducers. The only reason why they got rid of ZDDP in most oils (except HDDO's like Rotella) is that catylitic converters are required by Federal law to last a lot longer than they were before. It used to be 50,000 miles before OBDII and now it's 80,000 miles. I gaurantee our pig rich AF ratios and high EGT's will cook our cats long before ZDDP's from oil do, unless you're burning lots of it (smoking turbo?).
I take local race engine builders advice with a grain of salt when it comes to what I put in my street driven vehicle. How often are "race engines" rebuilt? Quite often. How often is my street driven engine rebuilt? Hopefully never. Race engines aren't built to last. They're built to make max power, so one doesn't care if the oil they put in it will last for 5 or 6 thousand miles. Then again, if someone's got the money to build a race engine, why would they go cheap on oil and complain synthetics are a waste of money? If I'm going to change conventional at 3,000 miles to play it safe, but can go 6,000 on synthetic, the money spent is actually the same, if not less in the long run on a better oil.