FiTech EFI system

I dont have an MSD box, but Im running an HEI set up like what Trailbeast sells. It uses the GM 4 pin HEI module like you mentioned. Not sure if that is important though. I guess what would be the benefits of using the timing control vs. stock set up?
Timing control on the handheld can be adjusted via buttons, opposed to having to adjust the distributor with a wrench and such. There's really nothing fancy to it however. If you want to keep using the trailbeast kit, i have no issue with that. Just know the fitech would only operate in fuel only. If you want to do timing control. You need to add about $160 for a distributor, and maybe $30 for the rotor. Since yours wouldn't be compatible with the timing control. This does open up the cheaper 400 horse unit also, if you're not making much more than 400