Don't ever change anything on your Mach sound system
My Cd player stopped working so I went out and got a new one. When I had it installed I had to buy a $50 adapter so it would work. Well anyway I guess the new CD player put out to much power and it made my speakers soud like crap. I took it back to the installer and they said that the speakers are just not capable and that level of output. Why the F*** couldn't they have said that when I bought the CD player. Well anyway my only choices were to eat the CD player and return the broken one back in($440 invested) or get new speakers and totally get rid of the mach sound system. Speakers that sound like the stock ones cost around 1000 bucks! Either way I'm screwed So my advice to you is to never change anything, not even the head unit.
hmmm, that sux. I would be cautious of the place that told you your speakers aren't capable of handling that kind of output. The mach system uses amps to amp all the speakers anyway, that produce way more power than any head unit can produce alone. Plus, you can never have too much power, you just have to adjust your EQ settings on the deck (and not turn the volume up as much). I've had no problem with replacing my deck (got an MP3 player). I would look into their install, and the adapter they used as the prime suspect
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96 Mystic Cobra. Bassani Off-Road X-Pipe, Eibach Springs, WMS Racing Upper and Lower Velocity Tube, 87mm Mass Air, 30# injectors w/ adj. FPR, Flowmasters, Steeda Aluminum Rear Upper and Lower Control Arms, Steeda Sub-Frame Connectors, Stalker Front Bumper, Wings West Sides, Audiobahn audio system. 3.73 FRPP Gears.
I am the manager of a Best Buy car stereo Install bay and have been doing this for 7 years now. What you need is an item to turn your new decks output down, part # "PSI2". They are $39.99 and have worked on every premium sound ford product so far I have come across. Any questions email me at Juniorteck@aol.com
Yes, I know. I purchased one for that price when I got it put in. I think the place I went to just ripped me off and purposely crossed wires or something. It really doesn't matter now because I got all new speakers, Bostin Coustic, and they sound better than the Mach system. Thanks for being nice and helpful.
I just had my Kenwood Excelon MP3 player deck, a custom sub box, 2 10 inch MTX subs, a 1000 watt Kenwood amp, and a cap installed this all replaced my Mach CD player and then some and I have had no problems as of yet and I kept the factory interior Mach speakers.
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Cobra2k1
03 Nissan 350z (stock)
03 Mitsubishi Outlander LS AWD
Former 01 Cobra Owner & All Around Mustang Enthusiast
"You Can Put A Rocket On A Dump Truck & It Will Be Really Really Fast, But It Will Still Be A Dump Truck."
Don't ever change anything on your Mach sound system 
So my advice to you is to never change anything, not even the head unit.
