Katrina was a Cat 2 at this point in the Gulf. I suspect Rita is gonna make landfall as a Cat 5, or at least a strong Cat 4. The water just gets warmer and warmer from where Rita's at now to the Texas coast, and wind shear is of no consequence. When Katrina got up to New Orleans and the MS coast, it was 'just' a Cat 3..
It should downgrade before landfall, the guy on FNC last night said it will hit shallower waters earlier than Katrina did. The shallow waters should start to suck some energy off of Rita, but its still a major 'cane and a few mph here or there really won't matter much.
That may be what was reported, but Katrina came into Slidell, LA with winds of 174 MPH and gusts up to 190. That's a category 5, isn't it?