Just stick with the corolla man..
if you are going to be so tight about fuel consumption and this is obviously your first turbo car after the above comment, you are going to be driving the ring off any car you get, and therefore the fuel consumption above of 11/100km is never going to be seen by you.
If you want cheap, low fuel, rwd car, get a CA18det or sr20det powered Silvia or 180sx.
they will use less fuel than the skyline and be turbo and rwd and lighter to boot.
why not 4agte your current car?
or you want fast and cheap, get a EP81 starlet.
or a 4agze AW11 MR2.
MR2 is rwd and supercharged.
A non turbo with extractors, exhaust and intake will still be a slow hunk of crap and you will spend your days wishing you bought a turbo one.
then try to sell it to buy a turbo one only to find that you were the only clown that wanted a non turbo skyline.
and end up selling it to some noob P-plater for FAAAAAAAAAAAR less then you paid for it.