Is200 Loom Change

[ISW200lawdz]

iv just changed my interior in my is200 for the half leather heated seats to get the heated seats working I changed both looms running down from the fuse board under the dash to the rear lights. everything is working fine except the rear speakers. I have two is200s 1 for parts which is 2000 the one I drive is 2001. is the sound system different?? the speakers used from stock are anyway!! I had to change the rear speakers to fit the looms for the heated seats as the connectors were different I know my 00 lexus has an amp, im wondering if the 01 has 1?? because the speakers have absolutely no bass and sound *BLEEP*

also id like to point out the 00 had all the extras sunroof 17" wheels etx while the 01 was the base model

thanks for the help :)