Greetings all, im curious how easy it would be to throw a gen 2 GTE head onto my 5sfe block to maybe make some power?
or do some of you experts think it wont make much a difference.

really id do it because my head has a pretty good tick and i wondered if switching to the performance head would be worth it as i can pickup a 100$ nearby
and potential hp gains would be cool.

thanks for any help

Bolts right up! Don't forget to throw in custom pistons, standalone ECU, injectors, fuel rail, wiring, custom intake, exhaust, and you'll be making some powaaahhhhh. Not sure how much more, though, as the stroker 5S crank won't want to rev as well as non-stroker 3S. So you may or may not hit the 180hp or whatever non-beams 3S-GE makes, but somewhere b/w 140 and 180hp is in your future.

would the standalone ecu and pistons be necessary? id have no problem with doing some porting and fuel upgrades, but will the 3sg(t)e head run off of the 5s ecu?

It'll "run", as in start and rev, on the 5SFE ECU. If you're looking to tune it to make any more power, that's not happening. I suppose you could install larger injectors and hope that enough of the fuel map coincides with the new engine's displacement, and then your engine will run pig rich at idle. But really, tuning the engine with injector size is not how you want to tune the engine. Worst case, you blow the engine up because the ECU is trying to control an engine it cannot.
You could try a piggyback, but any decent piggyback (Greddy eManage Ultimate) costs $400+ and will cost as much if not more to tune than a standalone, so it only makes sense if you need the stock ECU for govt emissions purposes.
There's no such thing as cheap power gains.