You'll need a rising rate fuel reg for sure.
Flex fuel sensor and piggy back for the
ECU.
Big arse injectors.
Walbro 460 - get the new gen version with the 120psi relief pressure.
Surge tank system.
You'll need to upgrade your wiring in the fuse box if you're running bigger pumps.
My Walbro 460 melted the fuse and relay in the box.
If you're replacing your fuel rails as well it's going to get really expensive.
Tuning time is basically double for flex fuel where a straight e85 tune is much cheaper.
Are you on a stock
ECU or aftermarket?
What turbo are you running? that will make injector and pump sizing more realistic. Just saying your targeting 28psi doesn't mean much if you know what I mean.
What power figure do you have in mind?