i dont know dude, primax is pretty shitty, theyre like, what, one-fifty a wheel or something? just my opinion of course but if your gonna get 17's id get a nice wheel and if you prefer not-so-nice wheels, id get 18s or 19s to offset the horrible aesthetics.
with 17's your tires will be smaller on the sidewalls so the overall diameter from top to bottom of the wheel/tire set will be about the same, maybe less than stock. (for instance the stockers are 16 inch wheels with 205/55 tires. estimate tire sidewalls at 4 inches each, so add 16"+4"+4" and you get 24 inches total. with an 18 inch wheel the sidewalls would be closer to 3 inches each which totals 24 inches as well, so they are almost the same size. i think my 18s were like .2 inches bigger with tires than stock.
offset: this is the measure in millimeters of the distance from the hub area of the wheel (where the lugs bolt the rim to the car) to the outside of the wheel itself relative to the width of the rim. imagine looking at the rim with no tire from a side angle where you cant see the wheel face. measure from the lug holes to the outside edge of the rim and subtract this number form the width of the rim. if it is zero then your offset is 0. otherwise your offset will be positive or negative. ours are 45 millimeters i think.