Help AEM or FCD whatever it is?

Guys I need some advice. My car has been moded with an HKS TO4Z single turbo and now that its run in I'm going to sort out the fueling and get it mapped. I'm putting 680 injectors on as believe these are best as any bigger and I'll have problems with idol and these are good for 750bhp - 800bhp. However my question is about the AEM? I don't know too much about this. I can't remember what they said but he wasn't sure what way to go. AEM or the FC.... can't remember now. Got baffled with Letters. How good is the AEM and is that best?

AEM/Power FC/HKS Fcon Pro V/MoTeC M800/Autronic SM4

These are all full replacement ECU's and can all be fitted to the MKIV....find a good tuner and fit what he wants you to fit. That is the "best solution". MADevelopments are pretty much the best out there...

Injector wise....you have a 67mm Turbo good for 750BHP on RACE FUEL at stupid boost pressures. I assume you won't be pushing it to the nth degree so 720cc injectors should see you right 680's might be a bit small....but you could get away with it if you raise the fuel pressure. There is a rule of thumb that works for our engines, and that is 1cc per 1hp. So 720cc injectors should support about 720BHP.

Thats it Fcon Pro is what he said. He's going to let me know whats best. I did raise that concern about the injectors. Thought for the set up I've got 680's sound small but wasn't sure. He told me that with larger injectors you have problems with idol and that I'd be wasting money. He has already built a sup putting out 750 bhp and 700 pounds of torque using 680's. I've pretty much left it up to him as he's not let me down yet but just don't want to end up wishing I went for 720's cause I can't get the power I want.