Banks Speedbrake on a Duramax

I have the banks speed brake on my 07 duramax LMM and have been pleased with it, it is too aggressive at any setting without the trailer but with the load of the trailer it works great. I use the auto setting most of the time. The only problem I had was after the installation the connector on the Allison transmission started leaking and had to be replaced , not a big deal but I think it was due to plugging and unplugging the harness during the install.The Speed brake holds speed during long downhill grades like advertised. I have the IQ interface. Do not get the GPS card that did not work well at all, I sent it back for a refund.