Traded in a base-model Grand Prix for the LT and haven't looked back. Sure the Grand Prix had a bigger V6, but she turned like a cow, fat too. Havent had the chance to use E85, not that it really matters to me, although great mileage for the size and driving conditions ~27 MPG avg would definitely recommend, especially with the great leasing options.
Lumbar support. No, seriously.
Plastic steering wheel has some uncomfortable seams.