Ok well I just had a new stereo put in my car. I have 2 JLw7 13.5 subwoofers in the back. I went to do a power brake in my car and the clutch slipped real bad. I think the weight of the subs weighed down my car so i cant power brake anymore. Anyways, while i was driving home, i had no power. it was like I had my clutch pedal partially down the whole way home. It felt like the pressure plate wasnt putting enough pressure on the disc. I lost pedal pressure for a couple seconds but it springed back up when i flicked it with my toe. Is the disc worn? Im going through clutches like crazy!!

 

I dont think that has anything to do with you installing subs into your car. If that were the case, your could would have problems if you were driving with a really fat person or a lot of people in the car. I would check your master cylinder if your clutch felt like crap, if not that check out your clutch.

 

Correct me if I'm wrong, but power braking is done on a 4-speeder auto, isn't it?

From what you described, my guess is $100.00 and a new clutch.