In summary all have the same 182bhp engine,
The 182 - comes with all the toys (CC, Leather, Xenons etc), comes in a variety of different colours and it is possible as an optional extra to have the cup suspension and cup spoiler pack fitted.
182 cup - is basically a 182 minus a few toys, no leather, no xenons but comes as std with the cup suspension and cup spoiler pack. Available in racing blue and inferno orange only. Weighs 20kg less.
182 trophy - based on the 182 cup but has expensive dampers and better suspension. Only 500 or so made and comes with different wheels and only comes in red, it also has recaro front seats.