Air Conditioning tips?

My AC compressor is almost dead on the 99 burb... had the pressures read and apparently the high side is running up and down between like 150 or 200 and 250 and the low side is staying up at 100-150. This supposedly indicates a dying compressor that can't keep pumping the high side fast enough. Well, I'm ordering a new compressor and drier. I see that many people replace an orifice on the condensor. I'd like to skip some labor, but is this a bad idea?!? What are musts, besides a drier replacement when changing a compressor?