Hard to Start
the first step is to determine if the issue is fuel or ignition so your not chasing your tail in the diagnosis:while its not starting make sure you have good spark(at the spark plug end of yr ignition wires) if you dont with your new electronic ignition double check your install(that the hall effect switch is set properly on the distributor cam assuming thats the set up)and that you have a full continous 12v at the coil and that the coil isnt intermittent. once it is running and warmed up check the timing aswell.
ill assume cap rotor plus n ign wires are in excellent shape.
next is fuel. ill assume clean n fresh fuel.ill assume the filter is clean and you are getting the right fuel pressure at the pump. refer to a maint manual for yr A4 as to the volume of fuel you should see in a cup after cranking a certain amount of time or a specific PSI of fuel pressure the pump should make. next that the choke is closing all the way and float level in carb is correct and that the idle muxture screw isnt set too lean and the accelerator pump is working.
Im sure others will chime in but these are some likely basics to start you off