It depends on where you're starting from and where you want to end up.  In addition to the 20/20, you will need the Rowflow module to run the hydraulic drive.  If you've still got the old three wire seed sensors that were on the early 7000's you will need to upgrade the tubes, sensors, and planter harness to be able to utilize the 20/20.  If that's the case I would upgrade to Precision's Wave Vision sensors.  They're not much higher than new seed tubes and high rate sensors from Deere.  They may even be cheaper.  They are a lot better sensor.  New harnesses can be obtained from Ag Express pretty reasonably.  Rowflow will allow you to use row shutoffs, which are valuable if you have a lot of point rows, but they are expensive.  

By the time you get everything on the 7000  to make it  a high tech planter, you'll have way more money in Precision parts than the planter is worth.  There's nothing wrong with that as long as you plan to run the planter for a long time.  I got to the point on mine that the 7000 wasn't heavy enough to no till beans into standing corn stalks without adding sand to the insecticide boxes.  I bought a 1770 and stripped off all the Precision stuff to put on my "new" 12 year old planter.  I sold the 7000 for a reasonable price considering that I bought it well used and ran it for nearly fifteen years.  It did a great job, it just wasn't heavy enough.  I'd like to add hydraulic downforce to the 1770 but with $3.00 corn that's probably not going to happen for a while.  Hopefully I can run the 1770 for another fifteen years and let the kids worry about the next one.