after driving so many cars, I dare say that the Waja engine is quite economical. But of course it cant beat the newer engines like City (both iDSI and VTEC) or others. Do remember that Waja is also a lot heavier.
To me, if you drive a 1.5L car, you will not feel much difference in terms of fuel consumption.
The rear fuel guzzler now is amazingly the Gen.2 auto!