The new 3.5L V6s have several improvements over the 3.5L's that were available when the VehiCROSS's were originally manufactured. If I'm not mistaken the new 3.5L direct injection motors also produce about 20 more horsepower than the older 3.5L engines. They also retail for around 5 grand so unless you have some very deep pockets, such an expense might be a tad bit overkill for a six year old vehicle.