Heya Scotty I've got a 1995 corolla with 300,000km on the clock that stalls under heavy load/hard flat foot. I've changed the fuel filter (looks like it was still the one from factory) and horrible brown fuel came out. After this was changed there was a big difference and the car is now able to rev out all the way but still stalls when taking off if you don't baby the throttle.
I've run a tank of premium with a bottle of injector cleaner through it to no avail.
So at this point I called up the auto parts store and got quoted $120AUD each.
But having a look on ebay I can find aftermarket set of 4 injectors for about the same price as 1 from the parts store. Are these any good or or are they yet another piece of crap coming out of China?

Also before coming to the conclusion it was the injectors here's what I've replaced.
Distributor cap
MAP Sensor (threw a code for the old one, hasn't come back since replacing).
Spark plugs
(leads are fine were replaced not that long ago and confirmed with a spark tester)
Fuel filter
Air filter
Throttle body clean
Checked for vacuum leaks in the intake (none found)
Coolant temp sensor
Coolant flush & change