I never realized that oil-talk could be so addictive. The expertise many of you have developed is amazing , and I'm hoping you could lend me some of your knowledge in the form of opinions. What oil weight, filter and change interval should I use? I live in South Florida and I have been considering switching to synthetic, specifically Mobil 1 becasue of it's OTC availability. Both cars see 80% highway use, with very few (5 times per week per car) short trips under 10 minutes. - 2002 Toyota Sequoia, 12K miles, 4.7L V8, driven 30K miles a year. Switching to synthetic at 15K. - 2003 Infiniti G35, 3K miles, 3.5L V6, driven 36K miles a year. Switching to synthetic at 7.5K. I had planned on M1 SuperSyn, 5w30, at 7500 mile intervals, with a Purolator oil filter, (Pure One, if available). Oil weight is factory recommended and 7500 miles is the interval for normal conditions. I plan on using the stock paper air filter since I understand K&N lets dirt in. Your opinions and recommendations will be greatly appreciated.