The wheel size is the same for all the GE6 Jazz's, there are just several model numbers which have other differences (Lights, bumpers etc.)
I live in Switzerland and have seperate 15" steel wheels with winter tyres (176/65 R15) and alloy wheels with summer tyres (185/55 R16).
The only advice I would give is DO NOT go for the cheapest unkown tyres. I have Semperit Speed Grip 2 which are middle to higher class but do not cost a fortune. I would also consider Dunlop, Pirelli, Continental, Michelin although these cost a bit more.
The good tyres handle much better in dry or wet and on snow or ice.
If you go to the Swiss Breakdown Service (TCS) website you will see several tests they do together with the German ADAC for a couple of tyre sizes and you can get a general idea of which are good and which are bad. Search "TCS wintereifentest 2013" and there is a PDF attachment. If you hopeless at German use google translate
Below 7°c in any weather condition winter tyres will perform better than summer tyres due to the softer rubber compound and tread pattern.