not sure if this helps but at road atlanta in our 4 speed auto racecar we were hitting 8k with the cobb race app and we did that for 12hours straight and the 4 speed auto trans held together fine.i think a swap over to the 6-speed trans would help even with the 4 port motor.

its seems to me if you use the 6speed at trans with matching ecu tcm and gauge cluster it would all work.just leave your 4 port fuel injectors and simply plug in your 2 primary injectors and 2 secondary injectors and your good to go.on our race car we found that our secondary fuel rail was actually way to small for the track and at top end we would starve bad even with a walbro pump so we installed a 6 port lower intake and used the larger secondary fuel rail and only used our 2 blue injectors and the car runs alot better so there are all kinds of things you can do once you try them and test them to see what works.

 

I have an 06 6 speed id like to turn into a manual, if you cover shipping for my transmission and the price we can work something :D