My Advice...Sell The Car Or Overhaul It....The ECU And Wiring Will Not Cost More Than About 10k-15k.....
For Smoke...Do Dry/Wet test...If Compression Are All Good And You Have Smoke Issue...All You Need To Do Is Get Valve Seals Changed...
Even Changing Rings And Seals On This Engine Shld Not Cost Above 10-15k Itself...A Proper Mechanic Who Knows Work Can Sort This Issue In Less Than 30k...My Rough Guess
I Have Been Through These All...Changed Swap Engines So I Know Yard Engines Speciallay A Series Do Need Ring Changes Due To Failure Blockage Of Its Favorite Oil Ring Issue
Swapping And Expecing 15km/L From 5AFE Is I Guess A Very Tough Call
My Advice Remains Same...Sell Or Buy Later Gen Car And Invest On Purchase Money ...Or Find Someone Who Can Mild Rebuild This Motor ....@vaqas1 had enough of these things mentioned with his car...contact him for better advice of mechanic
Regards