You can use an A4 coil pack on an A3 even the 92/93 corrados that
came w/ a coil pack.  Okay, I know your all saying I'm full of it but
your wrong.  To use an A4 on an A3 (whether obd 1/2) the connectors on
the ignition module are different.  Coil packs fail due to the coils
either cracking or short'n out.  So what does this mean?  Use your
ignition module from your junk coil pack on an A4 coil pack.  All it
is is swapping the modules from one to the other.  I have done this w/
success...you don't need an electrical engineering degree to do this.
If you don't believe me, compare them when you take them apart.
The cylinders are marked along w/ the ground.