is there an easy way to change the amplifier?

[jimmythemufflers]

Ok, so i have a 2003 base boxster with a cd player, no nav and speakers in the doors and dash. From what i can gather, there is an amplifier powering those 4 speakers in the front trunk.

Is there an easy way to put an aftermarket amp in and reuse all the wires and harnesses and NOT run any speaker wire? I prefer not to cut or splice anything. I read a post that crutchfield has one but when i called i had no luck. I am looking at a mb quart 240 watt 4 channel, nothing crazy just enough power to get some quality sound with the top down.

Please dont tell me to upgrade wires, head unit etc etc. Amp and speakers thats all.