Wow, that Texas guy is full of shit, and his tuner should be shot on site.

450cc injectors are good for around 300whp. +/- 5%

880cc injectors would be more along the lines of 600whp.

The reason you don't go with TOO big of injectors to start out with? Because it makes tuning the car more painful.

If your goal is to make 250whp. Go with some RC 440 injectors and leave it at that. You have room to grow if you want to up the boost a little, and you also have the safety net of not running your injectors at a high duty cycle. Personally, I've never once had a flow issue with a DSM 450 injector. Sure, some people have, But no one I know. You could always get them cleaned and tested by RC if you were that worried about it. On a side note, generally, it's the resistors used with the DSM injectors that make them unreliable. Get a good low tolerance precision resistor set, and you won't have to worry so much about it. (or a resistor box in good condition)

Either way, your "tuner" is a fucking loon. Probably gets a good deal on those 880cc injectors and sells them at a premium.