engine harness for $$$

Denny, the Terminator X would be a good choice if you don't need to control a bunch of other stuff not necessarily needed to run the engine. I.E. traction control. The terminator X will run a DBW throttle body, so you won't need to use that extra conversion component. If you want to get crazy with I/O, there's always the Holley Dominator, but the cost is significantly higher and I don't think they have a pre-made harness for that ECU. Speaking of harnesses, the Terminator harness may need some mods for the blower, like shortening or lengthening wires. While I'm typing this, I'm remembering the Hellcats have an electronic blow off valve that is essentially a small throttle body. Is that what this blower has? If so, I don't know if the Terminator X can control that. However, it does have trans control and if you aren't using that, perhaps some of that I/O could be used for the small bypass vale.
The holley will also require you use coil ignitors, which is an external component that goes in line with the harness. They should come with the terminator X. There are some smart coils out there for the hemi now which will negate the use of the ignitors. I'm not a fan of this because you're screwed if you have a coil failure driving down the road- the local stores won't have a replacement.
I don't personally have any experience using the stock computer, but I bet it would be harder to find a guy to tune the stock computer vs. the Holley. If you want to speak to someone about the stock computer option, I'd recommend you reach out to Sublime Technologies, previously DIY Hemi. They specialize is making take off harnesses and computers work in hot rods.

Thanks Tim, I plan on taking the Whippled Hemi / Big Red to BDS (lower Indiana, right outside the Cincinnati area) for initial tune. BDS does the tune on the DSR 1150 and that engine is almost a mirror of what we are putting together for Butch's new Duster. They already have a good baseline to start with and also recommended the Holley components.

I just discussed the different electronic blow off (Whipple calls it by-pass valve) that DSR has on the 1150. Because ours is not going in a late model but a resto-mod, our blow-off is actuated by vacuum. How that actually functions is a discussion I will have to have with Mike @ Whipple.

Now all I got to do is get my contact at Holley to pull the gear.

Thanks for your input.