Does anyone know if the wiring is already in place for the sub on the non interscope equipped cars?

The sub is only £110 from Fiat so if it's "plug & play" i'd go for it for sure.

I'd have one of these if I knew I could discreatley wire it up:
http://www.pioneer.co.uk/uk/products/25/130/201/TS-WX11A/index.html

or any underseat sub.

I think I read somewhere though that you just can't take the head unit out of the 500 without special keys.