I have a 2003 V8 and my girlfriend has a 2003 V8, both SR5 4WD.
We swap vehicles from time to time "cuz that's how we roll" haha!
Anyway here are some things I've noticed. I was going to write "IMO" or "IMHO" but I find that term is WAY overused here so I refuse to use it. Anyway:
-they get about the same gas mileage.
-The V8 will need the timing belt replaced every approx. 90000 miles whereas the V6 has a timing chain which can go for way longer.
-The V6 is aluminum so if it overheats there is more chance the head could warp.
-From what I understand the V8 is a more proven and durable engine.
-The V8 sounds nicer, is smoother, and has more torque. Better for pulling a trailer.
-The V8 has a 5 speed auto transmission, the V6 is 4 speed.
-The more I learn about the V8 the happier I am that I got it.
One strange thing: My 4Runner had some kind of modification to the exhaust by the dealer by the previous owner so I don't have this problem but most V8's emit a rotton egg sulfur odor out of the exhaust under heavy acceleration.
Most importantly make sure you do the following if you buy a used one:
-I wouldn't go for one that has had more than 2 previous owners.
-Get one where the owner can show you service records.
-No major accidents
-Get a Carproof done while keeping in mind even that doesn't disclose everything.
-Get a FULL mechanical inspection done by a qualified mechanic; even if it costs a lot it's definitely worth it.
-The only exception to all this is if you are buying it from friend or family and you know the service history.
Anyway, that's my 3 cents....anyone care to add or debate??