Yep, I did use an isolator and mounted it in the center of the firewall on that overhanging lip. No problems with noise, and didn't prime the lines with antifreeze. I got mine from DPP and talked to them about that and they said all you had to do was fill it at the isolator, but leave the line clear. I don't get any bouncing of the gauge and no noise. It just works. I hear the dissenting votes from some of the guys, but some of the pics I see, the gauges, even though they are diprocols, look different from what I got. I too, wired mine into the dimmer circuit with a scotchlok and spade terminal, off the light switch. They changed the color from what the 03s use, not a orange with white. The 04s use a orange with darker line on it and there are two alike, one powered and one not. I had to check both with bulb circuit tester to tell which one to tap. Works great, they dim at the same level as my dash gauges.