hey i have a 2004 mazda 6 and i got some new rims for it. they are 18x8 with 225 40 zr18 tires. but they rub when i have people in the back. i want to add a coil over kit , but was wondering if theres any other tire size i can put on these rims. i have already rolled my fenders. and have a w7 in the back. i was wondering if a stiffer suspension would help, but what if i had people in the back would i have the same problem?