for me since i'm 2j, having enough ignition driver's to run sequential ignition means i don't need an hks ignition amplifier and i can run a bigger plug gap since it's not wasted spark...but for sr......it's your call..
being that it can communicate with CAN, if i'm understanding this correctly, you can run a newer guage cluster like an rx8 or any other CAN car, or put an sr in a 350z and have a working tach or whatever you wanna do.
as far as the USB connection.....if you could use your flip face head unit as a monitor with a bunch of guages on it, that'd be pretty useful.
but if all you need is a full stand alone with total ignition and fuel control as well as a map sensor..then all you need is a d-jetro power fc.
if you need/want 2 step, and all the other "racing" features and controls then you need aem.
i will say though that drivability is way better with power fc over aem cause aem is so damn adjustable that tuners usually won't spend enough time with the non WOT stuff....however with the ability to log on your way to work, you can pretty much tune that out yourself in a couple days of driving....
being able to control the fans is kick ass though, and all the other input/outputs you can set. when you need that stuff, then it's an easy choice.
you could even control one of these ^_^
YouTube - Sound Performance Quick Spool Valve testing and results!!! (http://www.youtube.com/watch?v=I6ZCOTFET6s)
this is the new hotness :D
so far i've heard many people test and see gains, and i haven't seen ONE person not see improvements....so....i think it's worth the cash, and i'm gonna try it myself.
there's other companies that sell knock off's but i personally won't waste my time/cash with bullshit parts and hope they work correctly, not come apart, and not send shrapnel into my $2300 dbb GTX42/94r, cause that'd be @#
[email protected]#$#@$% gay >_< lol
from local guys that have used it they say it works better than an expensive ass divided manifold with a twin scroll housing...which means...
undivided manifold (cheap), quick spool valve, and divided housing = AWESOME.
it's like having a variable vein turbo, and/or dividing your exhaust housing in half down low, then running like a normal setup up top. the best of both worlds......
and since you can set the aem to control the quick spool valve.... you're gold.
i hope some of that helps you make your decision.
the only other "craze" i haven't totally jumped on board with just yet is e85....really my only problem with it is....finding a gas station near me that sells it. other than that it's ~$2.35/gallon, but since you have to run 30% more fuel it comes out the same if not a couple more cents than premium pump gas....so for a couple more cents on a gallon you go from pump gas to race gas.... technology is great :D
best of luck,
Dave