Hmm, 13-14L/100km is certainly on the heavy side. I've driven a 1400kg 4-cyl 2.2L Vectra with 5-speed auto in mostly urban conditions, and I got under 10L/100km. Admittedly Sydney's probably not as bad as Singapore, but 13-14L is quite high.

Other choice - Accord Euro Luxury? It's closer to small money, though it's not quite a small car. The Passat here is also a good choice, but again, not a particularly small car.

Or, VW Jetta? Used A4? If you do get a Lexus, then by most accounts the dealer service should be a few steps above the others.