I just went from a 4 cylinder 1.8 engine to a V6 4.0 engine.
The pickup is tremendous.
With my little car, if I went up a hill, it was just gasping, and you could tell the tranny was working really hard.
Now in my v6, everything is very smooth, and no sudden shifts as in the 4 cylinder
I have to say gas is higher. The most it ever cost my small car to fill was $20.
I filled my car recelty at a 1/8 tank and it was $25, it didn't quite fill it, ($30 probably would have done it)
My DH's car is a V6 as well, and its very nice.