Fair enough.
Can't help feeling that piston replacement is going to be the best route, I do see your point though.
I know the feeling of going down an expensive route, but you say the car was bang on before the fuel mixup ?
So apart from the piston scoring, the injector damage, I cant really see what other damage could have been done that cannot be diagnosed without stripping the engine.
Or
Basically you have to strip the ancillaries of the engine anyway, you will want to take your new injectors with your new engine, so when this is happening half an hour will pull the head off and take the sump off to examine for any damage.
If your not driving the car anyway it might just be worth it, its not going to cost much more in labour if you have the engine replacement as your fall back position anyway.
You never really know how good a second hand engine will be either.
Just playing devils advocate, if it was a 2.0l tdi Id say bin it and start again but a 1.9....I might be tempted to fix the one I have.
Good luck though, its gonna hurt either way.
