Read details please, Erasing Halo 3?

[Xbox 360 Elite]

If I erase Halo 3 from the memory of my Xbox 360 and all the free maps I have downloaded for it, when I play it again, will I be able to download the maps again?
Also, I've played several times on matchmaking, will these records, for example the level 19 on matchmaking and the EXP. points I've collected will be erased too?
Please answer! It's really important to me. I do not care if those things are erased, I just want to know.

 

[Rob]

You will be able to redownload the maps, but it could take a while. All your records will remain if you use the same gamertag, as those are linked online to your gamertag.