janab,
your car is very well kept MashaAllah. and 1800 VRG is also better in fuel economy than super saloon. but your demand is a bit high for that model (1998). plus its also high on the mileage (80K). you see, mitsubishi gallant is a shaukeen car. parts and maintenance are very expensive. and after one or two years if someone wants to change it, then resale will be very low (and slow, not too many buyers). buhat dair mein aur buhat tor ke bikay gee!! its true for all mitsubishi vehicles.
i think if you revise your price to around 625K, then u will get alot of genuine buyers.
anyway, best of luck with the sale.