I own a 08 Tundra bought new, and have a lot of experience with the 4.0 V6 in the current 4Runner and previously in the Tacoma...
The 4.0 in the 4Runner is different from the 4.0 in the previous generation Tacoma. Dual VVT and more power.
For reliability I'd go with a 4.0 vs the 3.5 in the Tacoma. How it compares long term against a Tundra, don't know.
