you need to buy the TFI harness for the coil it just goes between the stock harness plug and the coil with the msd box wired to it...
http://store.summitracing.com/default.asp?target=esearch.asp&N=100&Ntk=PartSearch&Ntt=8874&x=18&y=8
well you dont need it, or you may already have it.... my $0.02