Originally Posted by Motion
Looking at the various designs the AA and ER stands out for the CNC throttle body flange vs the silicone coupler you found in others. AA and ER really delivers more value vs the pipe and two silicone hose solution(cost much less to produce). ER offers a version to be used with the oem DV's so that is a plus for those staying with them.
I don't know how the N54/N55 throttle body inlet flange is like, but if it's smooth with a raised portion(barb), which most likely it is since it does not use any sort of clamps from the factory, a silicone hose type of connection is likely to come off since there is no barb for the hose clamp to keep the hose or clamp from sliding off. You will never find an oem hose or race car plumbing clamping to a smooth fitting, it's always a barb. All those other ones...Stett and Vishnu are cheap and have design flaws in them in my opinion and may pop off just as easily as the oem if not easier.
It doesn't have a barb, but a groove into which the large circlip around the factory charge pipe snaps into place.