So, did you get your guaranteed car then? I have rented the "Guaranteed" fleet six times, booking a Golf.. (Brand new, first renter to drive it with 17 miles on the clock) and Audi A4's.. Booked the 1.9TDI and was upgraded to the 2.0TDI (Ok it doesn't sound much but it is about 30Horse power extra) The select guaranteed fleet will probably always cost more as they are not turned over as quickly at the rental stations...