i have this car, apparently its some sort of peugeot, dunno if you guys know much about them...

as you can see i have the standard 406 rapier alloy wheels, 15" in size.
im wanting to chuck them on ebay so that i can buy some nice shiny new ones, but ive never bought/sold wheels before, and it appears theres lots of "interesting" bits of info i need to look out for, such as offset, stud diameter and other things that i dont fully understand.
can anybody tell me the details about these alloys so that i can search for something similar, cos i dont want to have to change anything, let alone the expensive low profile tyres ive just bought at £45 each.
The wheels I want come with these details: 6.5J X 15" ET40 PCD 4X100, so im wondering if these are in any way similar to what i have.
cheers!