A larger AFM will trick the ecu into allowing more air into the engine than stock programing would otherwise allow. When matched with larger injectors the oem ecu thinks everything is stock, and is able to maintain the correct air fuel ratio. It is a popular mod in the MKIII Turbo Supra hobby. With the 7mgte, when swapping in a Lexus V8 AFM, 550cc injectors(stock are 450), intake/exhaust mods, larger feul pump, and a modest increase in boost, the mods allow about 400-450hp w/proper tuning from the stock ecu and 7mgte turbo.
The Supra AFM wont have any positive effect by istelf and will actually cause the engine to run leaner than the stock ecu can compensate for. I am not sure what cc the injectors should have been swapped to, but I would think they should have been swapped for the 22re turbo injectors. For optimum benefit the intake system and exhaust should also be modified to handle the increased airflow.
I wouldn't bring up the injectors, let him tell you about all the mod's that have been done. If he doesn't tell you he installed larger injectors and what cc's they are, I wouldn't buy the Runner, other than at a non running price.
