Q: Standard vs Pro

  Hi all,

  Scenario:  I want to buy Delphi 3
  Questions:  which edition I should choose? Can I upgrade Standard to Pro
piecemeal?

  Based on the price differential between the two editions (approx $150) I
am tempted to buy Standard and then upgrade to Pro if I like it. Is this
upgrade option available?

  Can I do it piecemeal?  For instance, can't I just "buy" the Data
Dictionary for Standard at a later date? What does Pro have that Standard
cannot be upgraded to have?

  It seems to me that Standard has plenty to get started with but I'd hate
to find out that I REALLY need some missing piece and that I must pay an
additional $249 for the regular Pro upgrade to get it....

  Thank you very much!
  Paul