Though I have never worked on a V40, it is more than likely the amp will be in the back as close to the existing sub as they could get it. The reason for this is the shorter the distance between the amp and sub, the less distortion will be present. After removing the paneling, did you notice if the amp was there? Check on the right and left side above the wheel well locations. <P>If you want more output, I say replace both the amp and sub. Since you dont want to replace the indash, purchase a speaker level amp. This will tap into the left and right rear speakers and use their signal. These amps should have a decent lp filter. Once the new amp is installed, simply run a short length of speaker cable to your new box. <P>Hope this helped, I own an '01 S40 and im assuming the basic organization is the same.<P>Be careful though, There is also a seperate amp somewhere in your car (probably under the steering column) that powers your rear speakers. This is because of the 6 speaker setup. <P>Good Luck, if u need any help drop a line and i'll see what i can do.<P>Jay Em<P>'01 S40: smooth bore throttle body, HID fog lights, and neon galore <IMG SRC="http://www.swedespeed.com/ubb/smile.gif">