I've used the stock set up with chrome box, Jacobs Pro Street and MSD 6AL and Digital 6. I can't say I've seen a huge advantage of one system over the others in a dual purpose vehicle. The Digital 6 is nice because of all the extra features it has such as two step rev limit, start retard, and so forth. But other wise, I can't say I've seen big differences in power, performance, or mileage between them.
There are some guys in my local club who are really sold on the Crane stuff. They say it works as good as MSD and is a lot less money.
Summit has a line of ignition products that also looks pretty nice. I'm sure they are just rebranded major manufactuer items, but their package set up gets an ingition box, distributor and coil for a couple hundred bucks. It is basically buy a system, get the coil free.
If you ever want to overload you brain with technical information, get the book "Optimizing your Ignition" by Dr. Jacobs. It contains loads more info on ignition systems than you would ever think you need.
