The three models are visually similar and produce the same putput although the spool rates are different due to the difference in internals, the impeller blades have a different shape on the CT9A compared to the CT9 and the CT9B has more fins on the exhaust turbine and bigger impeller fins resulting in a better spool-up than the previous models. As far as potency goes, the EP80 is preferred for its potency over the latter models making in the most potent EP in the lineup.
Like i mentioned earlier, there's a lot of limitations that you have to look at. You won't be running any fuel managment, and from what i've read of your posts, there is hardly a fuelling upgrade and given the low RON of our fuel (THAT INCLUDES HI-OC) i feel you'll be "wasting" money without any significant gain. I'll still advise you to leave the stock turbo alone(if its okay) add an oil cooler, modify the existing IC with a Cold water spray or something, add a powerful ignition.
