GNVYUS, I just had the Holley HP Installed by Don Cruz. I used his custom made wiring harness which was a direct plug and play to the existing connections. I also bought his smart coil adapter which bolts to the valve covers. Pretty sweet set up!
Since I am a Holley dealer and sold it to a few Buick guys (with requests for a few more) I decided to get with Casper's Electronics about making Buick adaptor harnesses. These will be similar to the current XFI adaptors. Currently, there is a shortage of a certain connector, once they become available Casper's can start production.
[/QUOTE my computer read 12.5 volt true the xfi plug&play hardnes the wire that reaches the socket read 13.6 volts