Hi Rickys1121
No you don't need to replace the coil
If you are fitting the unit to a Bis distributor you need to remove the pickup from the baseplate it was supplied with
I removed my distributor and stripped out the baseplate and drilled and tapped two 3mm holes for mounting the pickup , you will need to put some thermal paste under the pickup available from RS Components which helps to dissipate the heat generated
You can pick up your positive feed for the unit from the spare positive terminal on your coil
Whatever you do make sure you connect it up correctly
All in took me about a hour from removing distributor to back up and running
I think I have a couple of pictures I will post up for you