Hello again everyone, So I picked up my SSB SRT6 roadster from J S Benz in Miami today. It is running perfectly again. As you may remember I was getting the P0300 generic "random misfire" code during WOT. Checking deeper the specific codes were P0305 (misfire on cylinder 5) and P0306 (misfire on cylinder 6). I'm not sure this will help anyone having a similar problem but here's what they did:

They replaced the coil packs on cylinders 5 & 6. That cured the misfire on cylinder 5 but we still had a misfire on cylinder 6 / but now only at peak RPM WOT pulling 4th gear (like around 120 mph). It ran perfectly through gears 1st, 2nd, and 3rd. They reduced the fuel pressure from 60 psi to 55 psi and that fixed the issue with cylinder 6 too.

I don't pretend to understand it all (that's why I took it to the experts at J S Benz) . . . just reporting what they found and what they did to "fix" the issue on my SRT6. This one runs like a race car again! I'll be taking this one to the Fall Dragon as I had originally hoped.