hi all. i plan on lowering my stock 330xi and getting either 18" or 19" Miro m6 replicas with michelin pilot sport A/S tires 245/40-18 or 245/35-19. where do i start for lowering. do i just replace the springs without changing the suspension? i read somewhere that the xi suspension was softer, would the wheels rub if i kept the stock suspension and just went with springs? or should i change the suspension too? either way, which springs and which suspension should i use.