It's a lovely shape the E46 coupe, but your car is worth around 6-6.5k, and a 318ci 2003 only about 4 4.5. Also the 318 is hopelessly underpowered, I've driven one.
If it was a 330ci M sport, I'd say go for it, or even a 325, but not the 318. I reckon you'd regret it big time.