No. What you DO have to concern yourself with is that you don't keep adding stuff to the stock wiring. Make sure your fan and other accessories you add have their own fuse box and runs from the battery, don't add them into the existing wiring. You can add relays from the existing wiring to run them, though.
The existing wiring is pretty maxed in the amperage it can carry. Your stock equipment will not draw any more amperage than with the old alternator, but if you add accessorries it will ... that's when you run into problems.
I made the mistake of hooking my electric fan up to the stock wiring. It pulled around 10 amps. The first time the fan kicked on with lights on, my wiring started smoking. Fortunately I was in the garage and was able to shut it off quickly before any damage or fire started.
Also, I'm sure I was fortunate that the only wiring in my car that hasn't been replaced with new wires is the tail light harness, the turn signal switch and the wiper motor harness.
Don't run electric radiator fans from the stock wiring!
I would imagine that your starter selonoid is still in the engine bay, and your + battery cable runs to there. The + battery cable is capable of just about what ever amperage you could draw from it, other than a direct short to ground.
Therefore, you can run a heavy gauge wire from the + side of the starter selonoid to a seperate fuse block, and run all your aftermarket accessories from there. You can have the accessories switched by a relay from the stock wiring (relays draw very, very little amperage on the switch side) so that the accessories turn off with the ignition key, but don't run the accessories themselves from the stock wiring.
I mounted a fuse block in my engine bay which is where I hook things like my MSD-6AL, and the electric fan (before I yanked it out).
im running a 5 speaker stereo system, MSD ignition, and an electric rediator fan and have had absolutely no problems at all with them and the 100 amp alternator that i currently have /forums/images/icons/smile.gif