So I bought my 05 MCS last weekend, and the HK system drives me insane. No bass unless you crank it but then the mid range becomes super muddled and ruins the sound. So I have an alpine head unit picked out, then I am going to replace the HK amp with a clarion 4 channel amp. I am going to retain the stock speakers for now, to see how they sound with a different amp and headunit. If they still don't sound good I will replace them down the road. I will also be adding a sub and making a custom sub box to give the back a false floor. I'll let you all know how it goes.

 

Not a good plan, IMO. First, those HK speakers are 2 ohm (not 4, which is more common by a long shot), and unless your new amp is capable of being stable at 2 ohms, you'll have problems. I don't know of any reliable reports of amps' 2 ohm stability claims being accurate. I'm not saying they're lying, just haven't read any posts anywhere that an installer used one and made it work well. And I've read a TON of posts on replacing the HK system. (See my thread below...)

Further, the HK amp has the built-in crossovers for the front speakers, separating those signals internally then sending them to the speakers. You'd have to do this externally, including new wiring. Trying to correctly wire up a new amp - including wires out to the speakers - in the middle of that system will spin your head around.

 

The amp is two ohm stable.

 

You'd still be missing the equalization and crossovers built into HK amp. Replace the speakers at the same time and you'd be fine.