I just bought a set of HP Evolution wheels and tires from a prime member. They came with 5mm spacers for the front and rear. I used spacers on the front wheels and was told by a prime member that spacers are not required on the rears. The wheels are 18x8 and 19x9.5 and my car is a 1991. The rear wheels are against the calipers. I would appreciate any information from those that have the wheels if the rear spacers are needed.