I will echo some of the previous feedback with some of my own:
1. - Stay with stock coils unless they go bad. I've seen enough posts on forums and "customer reviews" to state the MSD ones don't provide a worth while gain and fail prematurely. The only thing they are good for is looking pretty. If you are in the world of modding, the coils on a 3100/3400/3800N/A are all the same. But from what I understand the L67 (3800 SuperCharged) comes factory with a slightly hotter coil giving a slight better throttle response (I have a set of L67 "blue plugs" on my Monte and 3100 powered Grand Am, little change, mod is not worth more then $15-$20 and that's what I paid for salvage coils).

2. - The factory wires are pretty good from the start. Same gauge wires used on the SuperCharged 3800 and the N/A 3800. Again, staying stock is good.

3. - One thing I can say about plugs, NEVER use BOSCH in a GM. Premature fail, all hype. I personally recommend AC Delco or I recently put NGK in our Impala (found the stock plugs from the factory were AC Delco branded NGKs when I pulled them out).

 

Great info from everyone thanks guys!