1)Injector duty cycle doesn't mean how long they are open, it means how long the ecu is requiring them to be open, when idc's are over 100% you are running static, and your injectors are too small.
2)James will have a car worthy of many controllers or standalone ECU system.
3) When you post questions like this, especially a site with a bunch of locals on it, who constantly jab at each other, you will get a bunch of unsupported and/or fraudulent answers.
Just my $.02.
Want to learn about the systems?
www.aempower.com
www.apexi-usa.com
etc..etc..etc..try searching forums for more than one type of car, and see how the general feel for the controller(s) is/are.
I'll let you in on a secret.
Everyone will love the s-afc, they are easy to use, cheap to buy, and apex-i has flooded the market with them, they have practically shoveled the units out there back door.
The other big companies (HKS, Greddy, etc) all have controllers, but they aren't as hyped up.
AEM has mixed feedback. The ones that get it, get it, the ones that don't, well their cars don't run, and you hear about it on every forum. Standalones are better than piggybacks, no questions asked. The only question you should ask is of yourself. How confident are you in your own personal learning abilities?
Every piggyback on the market is 'plug and play' thus allowing the user to say they 'tune' there car, when most of the time, the car would run better if it had no controller on it at all. Then there are folks who slap on standalones on cars that have no business using them (hence what quest was hinting towards). Finally there are actually 'tuners' out there that understand what IDC, A/F, ignition timing maps, injector pulse width (see IDC), flame fronts, detonation, knock, knock sum, fuel tables, fuel curves, fuel enrichment, decel/accel, etc..etc..etc.. what all that stands for, what it does, and how everything works together.
Sorry for the rant, but some of the replies on this thead just erk me the wrong way, but I guess this is the parking lot, not advanced tech/basic tech.
I think I am just going to hold back up in the tech forums, lol.
In the end, its his call, its just how confident he feels about his abilities/trusts the opinions of peers.