dbayd the NISMO has 245/40YR19 (front) and 285/35YR19 (rear). Going up to 20's you would decrease 5 in the aspect ratio i.e. 285/30/20 That would assume no drop. I can tell you that my vert is dropped with eibach springs and I have no hitting with 20mm spacers front and rear and stock 245/40WR19 (front) 275/35WR19 (rear) BridgestoneŽ Potenza. I don't think you will have a problem with them assuming the back spacing is correct. Hope that help a little bit. Look is tires/wheels section you should find exactly what you are looking for.