First off, before spending more money on flexfuel setups etc...have you considered just buying a larger turbo, would work out cheaper and more beneficial in the long run...
Secondly, i think the SS2 would benefit on E85, the lower EGTs are handy with the smaller housings..
IMO...Adaptronic or Link...Link is better, many would say best , Adaptronic is cheaper..and probably just as capable...how much better the Link is I am not sure...depends how much you get the adaptronic for..at 1500$ rrp, i would probably just pay the 1600$ for the Link..But HG does good deals on the Adaptonic if you bought a turbo off him , which you have, it can be had for 1100$..absolute bargain considering its capabilities..only thing extra you will need is an IAT sensor, 40$ tops...and a boost solenoid for 50$ should you wish to use the inbuilt boost control..by the time you sell your AFM, PFC and Boost controller you would have close to enough to buy an Adaptronic off him.. Also the support on the Adaptronic forums is really good and your supporting an Aussie made product....
I swapped out my PFC for the Adaptronic,(more by coincidence than intentional choice)..I feel its the best decision I have made in a long time, built in MAP built in boost control, Boost by gear, eflex compatible, plus some other stuff I dont understand yet, its a very capable unit..I will be utilizing all of it too in my new setup ..
I say Doo eeett, but dont expect miracle power gains....
Keep the Nismos..740 will be fine your only at 55% you got heaps of room..your turbo will run out of puff before they do...