No All season tires on 18in wheels (style 197) on 328xi??

[Blue Mountain Raider]

Hi, im planning on ordering this new 328xi that my local dealer has on the floor. it comes with sport package with the 18" + summer tires.

I asked the dealer to put on all seasons instead with no charge and the guy told me what all season won't fit on the 18". Is this true?

I want all season tires now because i dont wish to go through the trouble to put them on when winter comes.

the guy tells me only way to get all season is to put on the standard 17" and he said he will do an even trade!!! no way, because I will be spending an extra CAD $2000 for nothing.

please advice. Thanks