I did a JL sweep in mine. Only found the six you speak of. Might be more, but I didn't look any farther because of the splits I used, didn't need any more mounting spots. I left the rear subs out so I could get sound from the subs in the trunk. I had a cluster problem that the dealer blamed on the factory radio not being in the car. They also said they found a loose ground on the engine. Haven't had the problem since, been almost a month. I found it hard to believe the radio being out would cause all the prob's I had. So we'll see. Good luck on the swap. Bring friends if you do it yourself. Took 13 1/2 hours to do mine with two other friends. Car is built very well!
2005 IBM M6
Flowmaster Super 40's
Chris White Guage Changes
HPE Cam Package(S-Cam, AR LT's,Lingenfelter CAI,UD Pulley, X-Pipe, Ported Factory Intake)
BMR Drag Bags