The group a is far better than the std coil, but it's a totally different shape, the connectors are different so a seriously simple bit of wiring needed.
Imo coilpack from msd is monumentally overpriced, for near that price you can get another ecu, for a little more a ecu/loom and set up.
The coilpack is NOT a cure all for ignition problems, if even thinking about coilpack the first thing I'd do is ditch the std ecu and go after market, which has coilpack as well as load of other features.
tabetha