I doubt any of us would be able to tell the difference between the two if not for the price.
That said, I have a Wagner and have no regrets, but I wouldn't hesitate getting an IE, mostly because if the meth bung, but secondly I suspect it has the better bar and plate core which dissipates more heat (but I've only seen the outside and not the inside of the tubes)
Between the two, go with what you can afford and you'll be happy. Don't worry about someone having all the same mods except that other intercooler and being drastically different, I doubt it'd even be measurably different without lab equipment.