The timing belt on 3.4 is easier to change because the 2.7 has a chain..... which may last up too 200K. I have 99 2.7 with supercharger, It had plenty of power for me before SC, but wanted more!! I wouldnt go with the 2.4 yota, but stand behind the 2.7. Is this truck and extended cab? I have standard cab model.