So what does the standard system consist of? While certainly no audiophile either, I have had decent systems (Alpine every time) fitted to a couple of cars I used to own - both were hatches so it was an accoustic shelf, decent 6x9s, a proper head unit and upgraded front speakers in each. Nothing earth shattering but both made good sound.
My intial instinct was the go for this upgrade too but I honestly don't think the standard system is bad at all. I play a lot of dubstep and so bass is critical - I reckon that while my home system (Teac, Bose, etc) is a lot better, the system in the car isn't bad at all.
My dad is a stereo bore (ex pro bass player with a penchant for serious ICE installs and home hifi) and thought the system sounded okay too. Nothing gob smacking but certainly no need to rush out and upgrade.
Where does the amp go? I might just check that the dealer didn't miss a hifi upgrade in the options list (a couple of others options weren't listed either)!!