hello all , want to update my situation on efi ...
With lucky i join the holley forum and FB group to know how to , and all what it concern having a sinper efi .
Well , it's not a point of view , are more than 20000 people  posting /helping /troubleshooting about sniper . 
Got to say is a holley forum born to solve problems , not for advise about new stuff . 
This numbers got my speechless  . Thinking that only half has bought a sniper ,,, are a lot of people in trouble.
Most of the times are always the same issue  , IAC , TPS , RFI . 
Always with lucky i got some answer from holley tech regard my issue . they suggest me to do the" tape try ".
Simply tape the inlet of IAC firmly and see if high idle stop or not . from the answer they can diagnose what happen.
Short story goes that my car is running as should , without high idle especially around 2200/2500 rpm . has desappear .  still have an incorrect idle when stop , still around 1100 rpm , but actually i don't feel any problem instead of 800 rpm like with carb . 
Now will be interesting to know what they think i should do .  Is this "tape trick " the reveal of broken IAC ? 
For what i read , yes ... but just today i found another good answer for the issue . 
THis is related with vacuum advance (that i still have connected to efi ) , seems gonna hurt with IAC vacuum . 
Don't ask me how ... not so smart to know . 
Sayd that the car is running great in every occasion , start , slow cruise , acceleration also at low speed with 5th gear . No more gas smell around , and ( just at the beginnin ) see is not so thirsty . To be honest in this trial and error  i am not so " gentle " with my car , so pulling , pulling , pulling all the ride can't be otherwise than guzzler . 
I will be glad to know if i got to " tape " forever and use like that or holley provide something for me . 
If this is the only issue i can fly over , and keep it . But i don't think i would suggest this to buy for a friend . 
Even the holley distibutor has problems also if is part of the kit .
Conclusion : Generally speaking the efi /tbi system can be a great gift but needs a lot of attention at the start up .
Spark cable , rotor cap , wiring lay around can be source of problems that can not be solved if on the other side there is something so "sensible " to go mad at every sparks occure . 
On the other side i haven't heard so much issue with FI TECH , as well i don't know so much . 
This sniper will be part of my know how , honestly i think a carby well done is top notch for old musangs . 
Alessandro