Our roadster did NOT come with the Harman Kardon sounds system. However, I'd like to install a used Harman Kardon amplifier to make things sound better. When I poke under the driver and passenger seats I am not finding any wiring for the amp. Does anyone know where the HK amp plugs in? If I'm missing the wiring loom does anyone know where I could source one?

 

My suggestion is to just get an aftermarket amp with speaker level inputs, and wire it in. You'll save yourself much headache.

 

What Nik said - you are much better off using a different amp or head unit with RCAs and a separate amp. Crutchfield with have the harnesses that will work. Adding speakers in a non HK is easy - I put tweeters in the upper door ( where the mid was ) and woofers in the lower door. And coax's in the rear. The HK amp alone will not help as you have the base speakers which are not really designed for the freq cut offs. Plus the HK is an 8 channel amp. You only need a 4 channel with crossovers.