My driving style is less conservative as compared to sdogar.
i use ik20s, an intake, change oil regularly at 3000kms, 30psi in all 4 tyres.
Normal driving, my RPM stays below 3000, but when in the mood i redline a LOT.
THe minimum i get is 11, which is alarming for me if i ever get it. Usually i stay between 12.5-15. Probably because my driving is on long routes mostly? highway or shahrah-e-faisal mostly.
BUt still, within city it should be 12-13 at least.
I've used my car for around 60,000kms now since 2010, never had economy issues.