The car is Dodge Dart 1967, I have no stock wiring and no distributor, have no chance to check what will fit...
OK. In that case you should first come up with a wiring plan, the type of ignition that makes the most sense for you, and the amount of time and effort you are willing and interested in spend adjusting the timing curves.
In my opinion, the last is the most difficult for most people. Difficult in that it requires learning the purpose, repeated testing under different conditions (unless it is drag race only, then it is just two conditions idle and wide open throttle), and physically removing the distributor - partially disassembling it, making adjustments, reasssembly, reinstalling, checking the the curve and retesting).
If you are building you're wiring from scratch then the Pertronix, or HEI module is just as easy as a Chrysler type ECU (shown in the kit Trailbeast linked). It becomes a question of priorities about availability and durability in location and intended uses.
With the info so far, I'd lean toward a mopar performance distributor (or the copy being sold be Eherenberg). The Chrysler (mopar performance) distributor will be stock dimensions. And a
good HEI module mounted on its own heat sink could have some advantage over the other two. I would think that in an emergency, HEI modules should be the most available where you are, followed by Chrysler type, and Pertronix the least - But that's just a guess.
Quality is the biggest problem with aftermarket electronics.
If you decide on using a 4 pin HEI module, then use a matching e-core type coil.
The objective difference in mpg and 1/4 mile performance will have very little to do with the system you choose if the engine has good combustion characteritics to begin with. See what Jpar wrote above about the MSD in the 1/4 mile. When the combustion is not so good, which too often happens with hot rodded engines or when trying to meet stringent emmissions requirements, then the longer, stronger, higher voltage, or multi-spark can sometimes help.