The IMAX 2000 is an antenna like the A99. It is longer and with the addition of the Ground Plane Kit it makes for a better antenna overall due to it being so much taller. From approx. 18ft which is how long the A99 is, versus the IMAX 2000, which is 24ft tall. Also make sure to get a good isolating balun, stay away from the MFJ products, they aren't very well made.
And again, if you have neighbors close by make sure that your antenna is up as high as you can get it as well as making sure you are putting out a clean signal. Another good piece of equipment is a good Low Pass Filter. The RF Limited DF3000 Low Pass Filter is a good one for the money. If you cake find a used Drake or Bencher. They are good ones too and can be found on Craigslist as well as a lot of other things you might need to set up a base station. Buy the radio new as well as the coax. Other things you can get off CL. That is JMO. There is a lot to setting up a proper base station and to make it work at its best. Yes you can throw one together and be on the air, no doubt. But it most likely won't work as good as someone that took their time and got all the necessary equipment needed. These are all JMHO's. I'm sure Matt will explain this to you. Be safe and again, don't rush things. The DX cycle is going to be pretty dead for a while!! Best best is to find some locals!!
73 and God Bless
222 Daytona Bch., FL