Hello, I have my Z4 wheels 8x18 ET34 and 8,5x18 ET37 with tires Bridgestone Potenza RFT (225/40R18, 255/35R18) and M-Sport suspension (code 0704). All in excellent condition. Now I want to reduce the suspension by about 20-30 mm. Just change the springs? Influence on management? What would you recommend? Thanks.