nav disc's?

[speedymacfish]

I've been reading a lot about sat nav disc's on here, and being a bit ignorant to the whole thing, i was wondering? where does the disc go? is it just a normal run of the mill cd that just goes straight in the unit? or is there somewhere else it fits?
I know owners here say get rid, but i'm a bit of a fiddler and would like to go though the hardship of finding out if it can be done.

Cheers G

[andy]

The box that takes the disc's is under the passenger seat on mine.