Dave: I queued this up this morning but never hit "send". I hope it is still pertinent to the discussion:
"A new coil could be either oil filled or epoxy filled. Not sure of my existing one but it is mounted horizontally. Any preference / benefits there ? Not sure of my wires either...any recommends there? I haven't seen my plugs...any preference there? "
CB Performance sells a Magna Spark II kit that includes the electronic distributor, the dry-pack coil, Billet coil mount (coil is mounted right behind the distributor), disti mount/clamp and a set of plug wires. This is the kit I installed:
It is adjustable (if needed) by getting inside and changing the advance springs and stops - pretty easy with decent instructions.
The 123ignition system is well over twice the price (at $500) of the Magna Spark kit for just the distributor, but it is adjustable via your smart phone on the fly. It is becoming popular with the original 356 set. It also uses traditional (old school) spark plug wires.
A couple of local original 356 guys have them and rave about them, but the cost was not an issue for either of them.