I would like to shorten ratio of the rear end of my 1998 SL500 from 2.65 to about 3.07. Obviously I would have to re-calibrate the speedometer after that change. Is there anything else I should be aware of? I am aware of higher fuel consumption but I am prepared to trade that for a better acceleration. Are there any kits with the proper gears on the market? Mercedes SL300 has a rear ratio of 3.45 but I understand that the gears are not as strong as the ones in SL500.