I actually already changed those to 8/35. I guess I was more concerned about the modem acting as a bridge. But after further reading I find that's not an issue.
The modems are pretty much interchangeable. The only potential gotcha is if you're signed up for the 10000/768 package - if your modem isn't ADSL 2+ capable, you won't get the speed.
Otherwise, I've used a variety of different modems without problems. -- The goal of the broadcast engineer is to get all the meters on the transmitter to go as far to the right as possible!!