Quoted from drbrain:

I know this is an older post but trying to get to the bottom of upgraded all 3 speakers in an Elvira Premium. I already have the upgraded plates from Speakerlightkits.com and the recommended Kenwood backbox 5.25 inch 1366 speakers. The Kenwood 5.25 inch speakers are 4 ohm and the Pyle PLPW8D 4/8ohm dual voice coil speaker has been recommended for the cabinet. It can be wired as either 4 or 8 ohms. Since all the speakers could be 4 ohms and I assume connected to individual channels, haven't checked wiring on Spike 2 to see if it is series, parallel, or direct, I know there is a setting in Spike 2 games that allows you to change to 4 ohm speakers versus 8 ohm speakers. I was curious what others have done and if anyone knows the wiring on Spike 2? Just don't want to overload the board.