I'm using the one I suggested, it works great, it is very easy to install and it doesn't have to be calibrated. It really helps when tuning your carb at idle or when driving down the road at cruz or WOT. It is nice to see any changes that you made with the idle screw, jets or metering rods.
I just checked it out on Summit's website. Man those instructions are ridiculously complex. For my intended use it appears that i just need to weld in the bung, hook up the gauge and go. ....I think.
