well bro for 1.7 you should be looking at anything from 18 to about 300 im guessing...... with beemers it depends a LOT on the seller and the model........ if petrol costs are not a big issue try gong for one of the Six cylinder cars..... 320i, 325i or 328i..... those are BRILLIANT!!!
but a 318i in good shape with a good maintainence history is a sound buy...... get the October issue of the Motor mag, there is a group test with the 3 series in it...... check the car that won!!
seriously though, if a 3 series is well maintained and has a low Mileage, he number is not an issue...... great cars are great cars, whatever the plate is.......
Cheers