In my case I have the 1.5 TSI with the K&N panel filter (in the OEM box) and the non-resonated Ramair wide intake pipe.
The behavior is similar to what you've described. The sound effect is subtle and non-car people wouldn't notice it since they don't have a before and after reference. And personally I like that. Its not obnoxious that is ruins the daily drive, and when required it sounds sporty and engaging.
With my combination of parts, you get a more aggressive intake suction noise, quicker throttle response (turbo spool up) and an audible pressure release when you lift of (reminds me a little of a horse sighing

, but not as in-your-face as a blow off valve).
The Ramair intake pipe also has a "negative" side effect. Since the turbo spools up quicker, it can also spool down quicker, and paired with cylinder deactivation, it can sometimes results in a little jerk / judder on very slow city drives.
This is not a big side effect, it just requires some readjustment on the drivers part.
All in all, intake mods will never result in massive differences. They are more of a supporting mod for when you start to tune the engine ECU. Only than can you actually benefit from the intake mods, since you reprogram the ECU to let it know what to do with the extra air and fuel it is getting.
If you are concerned with possible intake leaks, you need to ask yourself do you notice any decrease in power? Do you hear a hissing sound (across the entire rev range) that wasn't there before? Have you visually inspected or gone over the intake part seams with your finger to check for gaps?
If it all seems in order, than you are fine, and you are just a little disappointed that the "mods" didn't do their advertised claim (as is usual in car parts markets). Also if there is a significant leak, the check engine light would come on, since the MAP sensor would get low readings.