I have had my 03 V6 LS for almost a year now. Aside from getting some catalytic converters installed by the dealers my vehicle hasn't required any maintenance. I have had the engine light go on and off for about a month and it has not come on since. A dealership mechanic told me that I just need to replace the spark plugs because there were no major problems. I wanted to know what preventative maintenance( I.E. replacing brakes and rotors)should I invest in so that I can stay away from costly repairs in the future. Thanks in advance for your advice.