Powermac G5 1.8ghz NEED A DL DVD BURNER... What to buy?

As the title states, whats my best and fastest option for a drive to replace our old DVD-R drive on my GF's G5 Powermac.

In a previous life I dealt with PC's and you could just get any old drive, I am going to make the assumption (and possibly be very wrong) that you must buy only a certain brand/model of DVD-R DL drive in order to use it with the apple.

What I'm really asking is can I scoop a 20x DVD-R drive from newegg and plop it in there and get away with that.

Thanks.

sorry if I wasn't clear, I'd like to replace the internal one that is currently there as we are going to start using this machine much more, we need something much faster than was there.