Info provided by Calvin of Nivlac57 Youtube Channel

There were two styles of coils offered from GM. Below are the 02-05 coils (right), and 06+ coils (left). The 02-05 coils are ok, but at higher output, they are not up to the task. We saw serious ignition break up at around 14 psi, even when gapping the plugs down. It is rumored that internally the 06+ coils are identical to LS coils. We have had them up to 460whp with no issues, so far.

For those that wish to install 06+ coils onto an 02-05 engine, I am starting to sell adapter kits (coils not included). Here are some pictures of them installed:

LS Coils

Another option is to convert to LS coils. I did this with great success. They just are a little more ugly in my opinion.