Need Some quick help...

The Holley HP/ Dominator computers can idle and low speed in what is called "Alpha N" and then switch to the normal mode they use which uses your MAP sensor. Find out if the FI tech can do that or even run in "straight" Alpha-N at all times

Evidently Holley Sniper ---which does NOT use the HP or Dominator ECU--can not do this see this question

Will the Sniper EFI work on 600 HP with low vacuum at idle?

You have to remember that the FItech and the Holley Sniper are both low budget starter systems. They simply don't have some of the features of the more expensive systems.

Also remember that for a bit more money you could go with a Holley HP based computer and with a TBI setup which would still be a lot cheaper than multiport, and later expand it to such while keeping the same throttle body.