New speakers don't sound good

RonRizz

sounds to me like an install issue. I would have been wary once the shop guys told you they couldn't figure out where the wires went because of the last guys install. BS, straight up. A professional shop would have started from scratch, never trust someone elses wiring when you're putting your name on it.
I would look first at your crossover networks, since that was an issue they pointed out to you... It may be that they didn't use them on the woofers, and they are getting low frequencies that they are not designed for. Also, if you are distorting, your amp gains need attention. Take it back to the shop before you blow your components, and have the guys you paid to do the job get it right, or get a refund, and have someone else fix it.
If these clowns can't hook up a simple system like this, run far and fast, and shout it from the rooftops so noone else gets robbed.
Hope I helped.

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