I've got it on my car. I can say with certainty that having 1" ports on both your hotpipe and intake are key to killing the turkey. As for a dedicated vac line, it's obviously a good thing, but I can't say I noticed it making a real difference.
I still get a gobble or two when I let off the gas occasionally, but generally it's a much more pleasant "chirp-psshhhh". I think I need to regrease the piston, and the gobbles are coming from the valve not opening quickly enough at times.