I have a question about Forza 3

I just bought Forza 3 ultimate collection, and I didn't know that stig's garage car pack came on a voucher.

Now here's the deal I share my 360 with my brother, but we both use different accounts. If i download the DLC pack will it work with both of our accounts or only one of them?

I just bought Forza 3 ultimate collection, and I didn't know that stig's garage car pack came on a voucher.

Now here's the deal I share my 360 with my brother, but we both use different accounts. If i download the DLC pack will it work with both of our accounts or only one of them?