i'm installing new msd 6m2l boxes to replace my factory merc igntion system, however i still want to use my factory distributor. In the diagram they show to still use the igntion amplifier? is this my thunderbolt module?

yes you have to keep that hook up

I posted on the thread in GD.

Before installing the boxes get them tested,after years of me defending msd and never having any problems with there ignitions I replaced my std automotive msd box with the same ones you now have and was PLAGUED by a season of ignition problems. After the second box worked intermittently I bought a msd box tester for 150$,when box #3 showed up I immediately put it on the tester,it was dead on arrival!!. The problem I found was the wires are crimped going into the box which caused it to work intermittently or not at all,when I called MSD for the 15teenth time they had never heard of anyone else with my problem,I am done with them and I had too many trips to the water that required me to work on the ignition (at the dock returning it to stock for the day). It was never a poor installation as the msd box tester proved,you would wiggle the wires going into the box and it would work for a little while or you would hit a wave and the ignition would cut out/quit,Smitty