The Stock ECU drives the Stock coil packs which have the igniter built into them. most cars have the igniter circuit installed in a seprate box called the "igniter". without going into to much technical details lets just say its the igniters job to get the correct power signal to the coil so that it can fire the spark strongly.
On the EVO however, the Igniter is actually part of the Coil and the ECU uses a strange signal method called rising edge to drive the coils.
Under heavy boost conditions, this spark sometimes is not strong enough, or can be blown out, so it needs a little help - hence the HKS DLI which basically adds more power to the spark by amplifying the signal coming out of the igniter circuit to the coils..
the Gems ECU however uses a different type of signal circuit within the ECU which works differently to the stock system, and is not compatable with the HKS DLI
