G'day Greg,
Not sure about the difference between the two - but here is some useful info for you http://www.tackletour.com/reviewtdsolspin.html looks like the 2500 has in excess of 6kg of drag, at a guess I would say that the 2000 would be similar. If you are only using 8 - 10lb braid I don't think you'll have any problems with either.
Cheers
John