Pertronix Ignition

[Jim Davis <jamdav@woodward.com>]

Listers,
I was in the process of ordering a Pertronix ignition module and coil from
classicgarage.com, when I realized that there is an option of 1.5 or 3 ohm
for the ignition coil. 
After reading the recent "threads" on this subject I still have some
confusion as to what I need to order and modify in my car.
Can anyone run through the steps involved with this conversion.
Thanks!

Jim Davis
1974 TR6   (almost completed clutch repair)

PS:  Checkout classicgarage.com they have some really good prices.