You may have to sit down with a calculator and figure out if the lower interest rate (Zero % in your case, apparently) is going to save you enough money to overcome the difference in fuel economy.
That V-8 will chug some extra go-go juice, you know. Resale value might be worth considering, too. Jeez.....so many variables! Whatever you decide, just do whatever makes you happy so you don't have to sit around What-iffing yourself crazy for three years of payments.
Again, you're going to enjoy your 4Runner no matter which model you purchase or lease. They're good trucks. I just got back from a 1500-mile trip to Michigan and back. It was great - except for me having a hard time getting comfortable in the driver's seat. I can't pin it down, but you gotta get that sucker adjusted exactly a certain way or you get a leg cramp.
The 4Runner has acceptable road manners, good brakes, adequate handling and PLENTY OF POWER - even with the V-6. I consistently did better than 20 mpg on the open road, and I have a very heavy foot. Had I kept it close to 60 mph, I probably could have broken the 24 mpg barrier.
Anyway, good luck whatever you decide! You will learn a lot on this forum, sir.