TomF106SS, why can't you use the rear speaker for a connection to a line out converter. I have ran two subwoofers with two different cars using the rear speaker line and it never caused any issues and made it really easy to do it that way. The cars I did it with were a 02 malibu, and a 07 G6. I do agree with keeping the stock headunit and just using an aftermarket amp. That will give you the best sound quality cause now the headunit really isn't a factor any more.