The oil pan is by far the hardest part of the kits to install. Engine management is cake if you know what you're doing, however the Link leaves something to be desired for us people used to "real world" terms. TEC-II does as well, for that matter... tuning by VE is nothing short of a complete PITA.
Then again, once you get used to every system, it is simple to use. It's like learning to speak another language... or more appropriately, like learning the difference between building things with Lego's or Erector set pieces. They both can build complex things, the fundamentals are the same, just the methods are different.