I think most look at ignition coils in the wrong way. They are looking for performance gains and you dont always get that in an upgraded ignition system. In many cases you do, but not always.
The MSD coils are a more powerful coil and while it may not make a huge difference in power levels it does help with promoting better burns in the combustion chamber which can help with efficiency. If you get a better burn, that helps combat knock some.
Are you going to drop a half second off your ET's? Probably not, unless your stock ignition system just sucks, which the GP's doesnt seem to fall in that category. Can you improve your fuel economy and maybe combat knock some? Absolutely.
So depending on what your goals are in considering an ignition system, that will ultimately determine whether or not such upgrades are useful. Obviously, higher power ignition coils are going to work better with low resistance wires like MSD's also, so keep that in mind too. No sense in putting on higher power ignition coils and then choking that power down with high resistance OEM plug wires.
