Mk4 Astra GSi, SRi Turbo, Coupe turbo (can get most of them for under 7k if you hunt around, all have the 200bhp Z20LET turbo engine, can also get 1.8 & 2.2 NA coupes) or if youre not fussed about performance a DTI SRi (although they still pull well). Even a 1.9CDTi Mk5 astra? Can get them fairly cheap as theyre so common. Very good engines in 130 or 150ps. My dad has a 1.9TDI 150ps Saab 93 which is a good car, and goes well, buts its pretty big and i dont like the dash. My sister has a Cooper S and stuff keeps falling of it, everything creaks. Not impressed for 15k. Mk 4 Golfs are good, but lacking in performance in comparison to others, and pretty expensive repair/servicing costs.