You said something economical which although good on fuel a BMW is not going to be economical if it goes wrong. Civic 2.2d is a good engine but servicing is on the pricier side for parts. If your looking for cheap what about a fiesta 1.6tdic zetec? The 183 clio isn't a bad shout either, for 5k you'll get a minter and a little left for a mod or two