Well, it seems pretty obvious that you're running rich as long as you tapped your EGT guage in your exhaust manifold.
I might take a guess and think they installed your FMU in the wrong spot. I'm not sure though. Also, with the popping noise, that's not pre-detonation. You will in fact, here a loud pinging or knocking that's unmistakeable by its sound from what I head. Sort of like marbles in a tin can or machine gun fire or something.
You may be overloading on your O2 sensors right now as well with the overly rich conditions. (this is not good on your O2 sensors and is probably causing the "weird" readouts on your a/f meter) This may be causing a lot of carbon-buildup in your Cat to boot. (This will certainly lessen it's life span) These things certainly aren't "harmful" to your engine, but there probably will be a need to get some combustion cleaner and get rid of all the built up carbon that will result.
Try and lean things out, if possible. Closely examine your fuel system. Your fuel pump sounds like ti's operational as well as your FMU. You may just have things out of order or something. Your car WILL FEEL SLUGGISH under rich conditions. I wouldn't be surprised if you weren't blowing out some small puffs of dark smoke out your tailpipe b/c of the rich conditions. Furthermore, you probably are having a dirtier than normal tailpipe as well as carbon-covered spark plugs. (these things are all normal for overly rich conditions)
You will be much happier once you have resolved your overly rich conditions. Remember, although is rich is safe, rich is also slow and sluggish. It's hard to pinpoint what exactly is causing your fuel system to be overly rich without an ability to adjust your FPR. Since this is a system that we install, there are so many scenarios of a wrongly installed fuel system, that many of us can't relate to. Be thankful that you're not on the other end of problems and have an overly lean system in which your pistons could be cracking!
Things to consider: 1. FMU placement, error in installation 2. TPS sensor 3. faulty stock FPR 4. ecu problem
I would eliminate any problem with the vacuum lines though with your very solid 20 hg/in. reading under idle and rich conditions.
Good luck. Remember, your car was running fine before the install, so it's very probable that your installation is causing the problems.
Jason 98' Eagle Talon ESi-T Mitsu Super 16g Turbo(HRC)