Mickey's right, as far for me spacers with standard sized 195 rims proved to be useless. Some time ago I had a chance of getting a set of 15mm ones really cheap. After last winter I fit them on the car when changing steel rims/winter tyres to 'summer' alloys. The car looked alright and a bit more sporty, okay. It is also said that spacers may improve handling and make a car 'stiffer' in corners, but with stiff VTS shocks, the improvement, if there was any, wasn't noticable at all. Instead, there were two issues which eventually decided against using spacers:
1) annoying rubbing, especially on the rear wheel arches, each time the car ran over a larger bump in the road, and
2) a noticable decrease of steering accuracy on the front wheels. It was not so obvious when the spacers were fitted, as when they were removed after a couple of weeks - wow, the car again feels like a gocart now, compared to Queen Elizabeth's parade limo it became after fitting spacers
Maybe they're still the way to go with different rims or in smaller size (let's say10 or 5mm), or after making a mod to wheel arch plastic aprons, but as for me the pros are too few to overcome the cons. And compromising drivability for the look is something you must unfortunately consider when fitting spacers with stock wheels.