Negative Nancy here. Okay, so maybe my original reaction was a bit much, but I am a Gen IV LS owner/user, so the benefits are a bit harder to understand. Yes, I have also been working with HP Tuners for close to a couple of years now, so I do have amateur experience and am not just whining for the sake of Holley hate or being a cheapskate--I'm just not a shill trying to make a buck or get free parts. My LS is in a Ford, and I do not own any actual GM vehicles, so I am not here to represent the brand.
Gen IV LS = drive by wire throttle (not necessary, but why not use it?), and if you have an automatic, as you would if you bought a used unit from a junkyard, you will more than likely have a 6l80 (no good for Holley unit), not a 4l80, unless you got an older LS2 from a GTO, or a 4.8 from a 1500-level pickup truck. Do your own math here on the priced in "benefits" from Holley. I just tend to try and use what I bought with a complete engine . . .
With this in mind, were I to build a new (used) Gen IV LS for another car, which I will do in the future, the Holley unit does make me think of considering how much junkers are likely to mark up the prices of complete units, i.e., those that come with computers, wiring, front dress, and necessary (front) O2 sensors. All of these things must be priced in, even if you're buying a new GM Performance LS3 package. Usually, a complete junkyard engine/tranny setup winds up being a pretty good deal, but sometimes a new GM unit is actually a better deal. The ancillaries can eat a lot of dollars, if you're sloppy in buying. At Holley's price, especially with the extra 500 bucks they tack on for DBW and 4l80 control, they should be throwing in one of their Chinese manifolds and a set of rails. Fitech does.
So, say that you get a nice Gen IV 6.0 longblock with no intake or computer or wiring. A thousand for the Holley unit sounds reasonable. Just add a breadbox intake, injectors that suit your purpose, a van pedal, and you're mostly good. Add some front dress ($400.00 used?), and the price has climbed to a point where you should be seriously considering the complete (used) unit . . .
Oh, and HPTuners only requires additional credits for additional vehicles. If you are only tuning your own stuff, you should never have to buy additional credits (unless you own like eight different LS-powered things). There is of course a prolonged learning curve, but hey, wasn't this hotrodding, of which learning used to be a thing? My first time around, I paid a guy on eBay $300.00 bucks for a harness re-do and a Vats removal; it worked great. After this, I realized I wanted to learn to tune myself (and add a turbo and a cam).
Another point to add is that while it is cool that the Holley includes the wideband O2, there is a reason that people (like me and many others) still run narrow band O2s on a turbo (or NA) setup: The wideband sensors tend to crap out a lot more frequently (research will tell). I'm on my second one (AEM w/Bosch 4.9) in a year. From what I've learned, wideband O2s should be seen as tuning devices, rather than running devices, although I have never taken mine out since installing it (except to replace a bum AEM unit); I watch AFR while driving. I'm just an amateur, however . . .
The benefits are inarguably there, so long as your situation is perfect, and you don't purposely suck at math.
