I do have the center sump Holley pan. I had planned on using the TTI mounts and actually have them, but I had an opportunity to work with Denny on a coil over conversion before the G3 made it into the car. So now I'll be using HDK mounts.
Holley mounts move the engine forward 2" which won't allow the TTI headers to work. Moving the engine forward would also require a new trans mount and a new drive shaft. Oh, I run mechanical clutch linkage, so I'm sure moving everything forward would create loads of problems with that. It's a snow ball effect that I wasn't interesting in dealing with. Now that Holley has discontinued their headers, you are stuck with their exhaust manifolds. I personally don't see any advantage of using their conversion kit unless you want to use the SRV on a 6.4 and don't want to cut the firewall.