18's or 19's ?

[Dan020394]

im trying to decide what alloys and tyres i want for my megane its 2007 reg 3 door 1.6 extreme vvt
i am looking at these alloys:https://www.autoalloys.com/foxalloywheels?pmc_a=show&pmc_id=397
they are Fox FX004's and come in 18'' and 19'' the 19's come with 235/35/19 tyres and the 18's come with 225/40/18. They are both 8'' wide. I recon the 19's will fill the arches better but will they fitt without catching or would i have to fit spacers also will the 19's effect the speedo
thanks

Edited :

hi im thinking over gettin a set of 19's to go on the megane but i wouldnt be able to lower it as only being 17 the insurance would be ridiculous i was just hoping that some body could post up any pictures they have of meganes with 19'' or 18'' alloys that hasnt been lowered so i could get an idea of how it looks thanks