I am ordering a set of ADR Decadence rims for my roadster.

They are 18x8.5 and 19x9.5. The seller (Elites-Wholesale.com) says I won't need spacers, but that doesn't sound right with what I've read here on the forum. Will I need 20mm spacers in the rear to make the front and back line up with the wheel well the same?

Thanks for any advice.