[750hp]

Congrats on finding a car Linden. I know Motec tuners in SEQ, but you're in NSW aren't you?
A Motec start file isn't going to help you, because it sounds like it does that just fine.
Is there a data logging download port/cable? It would be interesting to see if there are any error codes when the engine lays over higher in the rpm.

You might find that a lot of the dialling in of your setup might actually be spent on the throttle bodies themselves. I've seen some very talented engine guys chase vacuum leaks and sync issues for ages with 8xthrottle bodies. When they're dialled in though, they look and sound incredible!

(It would be great if you could start a new thread with some pictures of the car!)