I didnt bother reading it all and CBF writing a massive essay so ill break it down
It can be done, its not hard at all
manifolds bolt up fine, dont need to change pistions thats crap.. Plenty of cars run 10:1 Comp
GTT aftermarket ECU's work, I run A PFC in mine. (secret quirrel trick to get rid of engine check light as GT's dont have traction control, dont know what that is? google it. Its what the stagea ppl do as they have hte same problem any good workshop cna do it). You can also run standard ECU with a piggyback to handle fuel etc like a Greddy Emanage Ultimate with the Ignition Harness thats sold seperately (required for r34 only)
The only parts that you cant get off the shelf are turbo water/oil lines they need to be custom (easy as) everything else matches up fine. except for a plazmaman plenum you will need GTT runners
So long as you have enough exhaust flow boost isnt an issue, Im pushing 250KW atm with standard motor, highflow turbo (at 14psi) and supporting mods and will be up to 300-350 with a turbo change.
Budget 4-5K if you are going to give it to a workshop to install and tune. Parts will set you back roughly 3.5K depending on computer choice.
The 25DE Neo motors are tough as nails so dont worry about throwing a rod unless you service your car poorly..
Wanna see how one goes? Come to the Texi in September and watch me..Or just look at my sig below