BTW, if you think that the engine is the only thing you'll have to replace with the kind of mileage you drive, you are sorely mistaken. Did you ever consider all the other stuff that ages on a vehicle? Just about every part under your hood has an estimate service life, and it might not be quite as long as you think.
Expect to cough up money to replace things like your alternator, water pump, catalytic converter, timing chain, and plenty of costly sensors (MAF, O2, EGR, etc...) when you really start to pile on the miles.
But now we're talking about the future again. Oh well, just wanted to give you a dose of reality for things to come. It's not like you're going to pop a new engine in a 4Runner with 200,000 miles and have a new 4Runner again.