Strutmasters is the world leader in suspension products for your 2009 Audi A4. We created the original air suspension conversion kit and now offer many other active suspension conversion kits (hydraulic, electronic, etc). With our EZ Strut replacement struts, control arms, sway bars, lift and leveling kits, and wide array of air suspension products we have the best suspension parts for your 2009 Audi A4.